Did Nico have a crush on Annabeth

There is little evidence of a crush on Annabeth but who knows, he is a fictional character and we have never had his point of view.

In the Mark of Athena, the 8th book, we find that Annabeth thinks he may have had a crush on her when they were younger there is no explanation and she has not seen him in a long time.

The first 5 books are all written from Percy's point of view.  We read that Nico spends very little time with any demi-gods except Percy himself.  There is just one line when Nico agrees to do something (come to Camp Half Blood), he says to Annabeth, just for "You." It is a big leap to read more into that line, which could so easily mean many things or nothing much at all.

Throughout the books Nico has only been close to one person, Percy.  They have saved each others lives many times, been on missions together and plotted together.  Nico is genuinely distressed when Hades tricks Nico to capture Percy, torn between the two Nico chooses Percy.