Possible cooling fan issue

I was in a Starbucks drive-through when my friend noticed there was smoke coming from under my hood. We pulled off into a parking spot and looked under the hood and there was fluid splattered everywhere dot on the ground it looked like I had leaked out all of my coolant and the cooling reservoir on top was empty. I put water in it to get me home and checked it when I was home and the water was still in there. My air conditioner is also having issues staying cold.
Nissan is saying that the leak is from a cooling fan which can be replaced under warranty. Can anybody confirm that a coolant leak could be caused by a fan because I cannot find it anywhere. Also, he said my serpentine belt is cracking and that is why the AC is having issues. But I feel like they are making this up since my repair was covered under warranty and they want to make their money.