The win over London Irish, the Saints' third in Reading in as many Aviva Premiership Rugby campaigns, pushed the visitors back into third place in the table and kept the pressure on the top two.
More importantly, the character showed in coming back from a 10-point deficit to overcome an Exiles side buoyed by the return of experienced back rowers Chris Hala'Ufia and Declan Danaher answered many questions that had been thrown at the Saints before the start of the Six Nations.
Although Nutley's score won the contest, the game hinged on two passages of play - the phases at the end of the first half which worked the visitors 30 metres upfield to put Stephen Myler in striking range to reduce the deficit to seven points going into the break; and Soane Tonga'uiha's charging down of an Adrian Jarvis drop goal a couple of minutes after the re-start which gave his team the impetus to go upfield and score a try.
Irish had started very much on the front foot. Still reeling and motivated from their Round 15 loss at Newcastle they showed their intent right from the off. Sailosi Tagicakibau and Hala'Ufia both made yards, and while Saints did well to force a pair of turnovers there was an element of fortune when Dan Bowden's pass out of the back of his hand went to the deck instead of the support.
Saints had been struggling to get their hands on the ball, but when they did it was to great effect. George Pisi made the most of the overlap outside him, with the supporting Paul Diggin hurdling his way up to the home 22.
The quick recycling forced the Exiles into coming offside, but while Myler's penalty grazed the outside of the right-hand upright the play had been as portent for what was to come.
The drop-out headed to the visitors' 10-metre line, but when Diggin caught Myler's bomb superbly it set up great position from which the Saints took full advantage. Play came right and then left, and when the defence ran out Noah Cato was put over in the right corner.
Again Myler's kick faded right but after having spent so long on the back foot Saints had the score they needed.
However Irish had showed in the opening 10 minutes that they deserved to be taken seriously as an attacking force, and in the second quarter they twice crossed the whitewash to put themselves in control of the contest.
A Jarvis penalty had reduced the arrears, but two minutes later things got even better for the hosts as Delon Armitage made amends for a couple of earlier errors by crossing the whitewash.
Like the Saints' score, this had its genesis in a chaser recovering a high kick; Topsy Ojo beating Cato to the ball as it returned to earth. But Armitage could also thank Tagicakibau, whose strength and balance kept him inches inside the sideline to keep play alive. Vasily Artemyev had the chance to sweep up, but he spilt the loose ball under pressure and the home full back was able to cross unopposed.
Myler and Jarvis exchanged penalties, but the momentum was firmly with the Exiles, no more so than when Tagicakibau got on the scoresheet himself. This time Saints were at fault, both for not controlling the ball in a promising attack and then for not getting back to nullify the kick ahead.
Cato was the covering defender, but he was overhauled rapidly by the chasing Armitage and with a bad bounce the try was a formality. It was a hammerblow for the visitors, but this actually prompted the few minutes of action that would go a long way to get them back in the game.
Myler's second penalty rewarded enterprise and patience, and then when Tonga'uiha's arms got in the way of Jarvis's attempted drop goal Saints were spurred to go upfield and score a good team try.
Diggin's break down the left, created by some good option taking by Myler, spread the defence. With the green shirts drawn to the play space opened up on the other flank, and as with the first try it was a fizzing pass from Myler that put the man over, this time Roger Wilson.
The tries may have been good, but with both being scored in the corner Myler was not being helped in terms of his kicks at goal. Again he was close, but not close enough, and although Saints were back in striking distance they were still behind.
It took seven minutes for Saints to get their noses in front with Calum Clark's decision to send a penalty to the corner vindicated by a third try. The maul had been causing damage, but the ball came quickly off the top and Tonga'uiha lunged for the line. Downey was next to get close, but again it was a Myler pass that earned the plaudits - and the Aviva man of the match - which zipped past Armitage's fingertips into Diggin's grateful arms.
The full back dotted down without being touched, and with Myler landing the conversion Saints found themselves five points in front.
The lead didn't last long, and while it was a rare Myler mistake - kicking the ball out on the full - that handed the hosts the position there was little the visitors could do to stop Danaher scoring in the right corner. Jarvis's wayward conversion attempt meant that with 20 minutes to play the result was still in balance with the score tied at 23-apiece.
Given the intensity and pace of the action so far it was inevitable that there would be plenty of replacements, but unlike in so many games their introduction did not disrupt the patterns of play, even if no further points were added in the next 10 minutes.
Irish came closest to a try, Ojo felled by a massive James Downey tackle, but with time running out Saints set out their stall once more. Ryan Lamb shaved the outside of the right-hand upright with a penalty and a fumble handed Irish a scrum just inside the own 22.
The tension was palpable and it was looking increasingly likely that a mistake was going to break the deadlock. Fortunately from the Saints' perspective it came from Armitage.
The full back took too long to clear his lines, Pisi came up with both the chargedown and the recovery, and Nutley was on hand to score not just the winning try but earn the bonus point as well.
REFEREE Andrew SMALL
9mins SAINTS Miss pen Myler
11mins SAINTS Try Cato 0-5
24mins IRISH Pen Jarvis 3-5
26mins IRISH Try Armitage Con Jarvis 10-5
30mins SAINTS Pen Myler 10-8
32mins IRISH Pen Jarvis 13-8
34mins IRISH Try Tagicakibau 18-8
40mins SAINTS Pen Myler 18-11
HALF-TIME IRISH 18 SAINTS 11
41mins IRISH Miss DG Jarvis
43mins SAINTS Try Wilson 18-16
50mins SAINTS Try Diggin Con Myler 18-23
55mins IRISH Try Danaher 23-23
76mins SAINTS Miss pen Lamb
77mins SAINTS Try Nutley Con Lamb 23-30
FULL-TIME IRISH 23 SAINTS 30