With the Leith side preparing to splash out a six-figure sum to land Josh Magennis from St Mirren, boss Jack Ross was this week forced to defended the club's recruitment policy after making staff redundant during the summer Covid-19 crisis.
Nisbet came with a £250,000 price tag when he moved from Dunfermline back in July but it already looks like money well spent after the 23-year-old moved to six goals for the campaign with another impressive brace.
Paul Hanlon's goal ensured Hibs kept hold of third place but it turned out to be an unnecessarily nervy finish as Ross' team switched off.
And it might have been a different story had Ofir Marciano not saved a Marios Ogkmpoe penalty while Hamilton were only two down.
Brian Rice saw an unnamed player withdraw from his squad this week after testing positive for coronavirus.
Regular number one Ryan Fulton was nowhere to be seen at Easter Road with deputy Kyle Gourlay handed the gloves for his first top-flight start and former Dunfermline goalkeeper Ryan Scully named on the bench just hours after being drafted in on a short-term deal.
But the 22-year-old made a confident start, pawing away a close-range Hanlon effort.
However, with Hibs swarming round the Hamilton box, the visitors could only resist so long.
That cynical foul earned the Londoner a yellow card – but worse was to come as Nisbet swept the free-kick away from Gourlay's desperate reach for the opener.
Accies did well to stem the tide for a spell but fell further behind as Joe Newell's cross was met with a sublime Nisbet header which licked the underside of the bar on its way in.
The Hibs defence had it far too easy in the first 45 minutes so Rice replaced Andy Winter with Ogkmpoe.
Hamilton suddenly had a presence in the final third and should have grabbed a lifeline in the 55th minute when the powerhouse Greek was wrestled down by Paul McGinn inside the box.
Referee Bobby Madden decided the last-man foul was only worthy of a yellow card and there was another let off for the hosts as Marciano sprang to his left to push away Ogkmpoe's tame spot-kick.
Gourlay made a couple of decent blocks to deny Nisbet his hat-trick but could do nothing as Hanlon nodded home after Christian Doidge headed a Melker Hallberg free-kick back across goal after 63 minutes.
That should have been that but Hibs were guilty of taking their off the ball in the final stages.
Former Hearts midfielder Callachan did what Ogkmpoe could not as he rifled his penalty home in the 75th minute after Porteous had tripped Kyle Munro.
The new Scotland squad member's night got even worse as he then diverted a Munro cross past his own goalkeeper with six minutes remaining but Hibs held their nerve to claim the points.