You seem to have a RT fare from LAX to SCL with a connection in ATL in each direction. The basic fare is $250.75 each way, for a total fare of $501.50.

My guess is that the fare code is XFLAX, which would be X class, but it looks too short. The NUC also doesn't look like a fare code, and N class should be coach award class, but this isn't an award ticket. I'm guessing that the 4.5ATL stuff is some sort of airport fee or tax. ROE1.00 could also be some fee or tax. The puzzle is that NUC appears where I would expect to find the fare code.

NONEND means that the ticket cannot be endorsed over to another carrier.

I'm sure that someone who's more of an expert than I am will be along soon.