When Nick is at Talbot's office and his holding a gun to his head AND Talbot's arm behind his back, he manages to open a door, while still holding Talbot's arm and the gun...in order to open the door, he would have to have a free hand, Talbot is never released and the gun never moves.
Nick is wearing a three piece suit when he goes to the seminar, but when he wakes up after the accident, he is only wearing a two piece suit. Not the vest. Nick tried to put on the vest when he was hurrying to leave his apartment. It was too difficult so he throws it aside.
When Nick is eating dinner with Alice, he is wearing make-up, goggles and a wig to disguise his invisibility. However you can also see his tongue when he is talking. Making his tongue visible seems unlikely nor was established.