The manager said: "Nick has come back from a serious injury, a big problem to a big area of the body for a goalkeeper. He has still been getting his rhythm back from the training work he has been doing.
"I am really pleased with how he's looked. He has continued to improve through training, every game I have a decision to make and that will be another one.
"We find ourselves in this position, and it is where we deserve to be. We will be hoping to finish off these two games strongly. We must make sure our players go to Manchester United in really good spirits, confident and prepared. Our motivation is to qualify for Europe.
"I need to look at them individually, I can't lump them together. Joey's (Joelinton) was a serious injury and required an op. I need to make sure he's the Joe we know. Not someone who is trying to find his rhythm.
"It's the same with Miggy (Almiron) and Nick. They're vital. Their presence is vital."