Aidy Boothroyd's side trailed Championship outfit Wolves thanks to Batth's goal in the 16th minute but drew themselves level thanks to Clive Platt just before the break.
If the Cobblers could have gone in at half-time with the score all square then the second period could have been tough for Wolves but the visitors edged back in front in injury time through Nouble before Sako wrapped up a place in the 3rd Round with just minutes remaining.
"My hope was that the players would give their all and leave nothing on the pitch, and I think they did that," said Boothroyd afterwards while bemoaning the 'very poor' goals that his side conceded.
"You hope you give a good account of yourself and I think we did that as well.
"We played some terrific stuff and at half-time it would have been difficult to tell which was the side from the higher level."