Trump not shaking her hand busted her ego.
I don’t really think he did that deliberately, if you look close at the replay he was already turning away with his eyes elsewhere.
He just didn’t see her, and she is just not important enough to waste time with.
1. The President didn't shake VP Pence's hand.
2. Nancy didn't give the usual introduction that included "It is a high privilege and my distinct honor" when announcing the President. She just gaveled in and said The President of the United States. I don't blame him for shunning her hand - if he did it on purpose, which I think he did.
3. I'm sure all the things she has said about him and his family over the last 3 years didn't help get her a handshake.