Nwaneri scored five goals as Arsenal won 7-1 on the day.
Wilshere said, “He actually really gave a new meaning to a game of two halves, right? He was quiet in the first half and I thought we couldn't really find him in those spaces and there wasn't enough movement from in front of him to allow him to get on the ball, but then, like I said, in the second half when I thought we were pressing and the game opened up a bit more, when you have someone with that ability and then, I saw a killer instinct in him today, he wanted that goal.
"Every goal he scored he wanted it. He prepped his touch and finished it nicely, but it's credit to the players around him as well for getting him those opportunities, pressing well, feeding him, and overall a really good team performance."
Arsenal reached the final last season, where they were beaten by West Ham.
Wilshere also told arsenal.com: “I said that to the players before the game.
“I showed them images of the final from last year and asked them to think back and remember that feeling and use that as fire and fuel to really have a go this year. Last year I think we were really good at taking each game as it comes, prepping each game and looking at the opposition.
"Again, it's going to be the same. We know that in the next round we've got Fleetwood or Liverpool so it's going to be a tough game. Two different games so we'll be keeping a close eye on that but we'll be ready to go there and hopefully show the personality we did tonight."