Paul Connor's looping header gave the Stags hope but Danny Kedwell rounded Alan Marriott to make it 3-1 and RyanJackson raced through to fire a fourth.
But it was the Dons - who play a level above Fleet in non-league's top flight - who got their noses in front when Nwokeji reacted smartly to finish after Rashid Yussuff nodded Ryan Jackson's cross back across goal.
And in the 'Star Bar', Dermot O'Leary will be hanging out with the likes of EastEnders Natalie Cassidy (Sonia Jackson), Michelle Ryan (Zoe Slater) and James Alexandrou (Martin Fowler) plus Alan Davies, Paul Kaye and possibly even the king of the jungle himself, Phil Tufnell!