The Gunners won 2-0 to reach the quarterfinals.
Nwaneri said afterwards: "I think we played very well. There were loads of different players playing. It's a completely new 11, so I think we came together. There were times when we struggled a bit, but I think in the end we did very well and came through with the result."
Nwaneri was keen to talk up fellow youngster Myles Lewis-Skelly after he helped set up the goal.
He said: "Myles and I, from a young age, have always had a good connection - he just sensed me there and I had the instinct that the far post was free. So I'm happy to get a goal.
"I think it gives us good momentum, going into the Premier League and the Champions League. We're just trying to take each game by itself and hopefully something good can come of it.
"'It's always nice to score at Emirates Stadium, it feels so good."