Does my panel have capacity for a dedicated window air conditioner circuit?

I have a window a/c unit cooling our upstairs room, an attic that was just finished when we bought the house. A lot of the electrical was redone when the house was remodeled but I don’t think they necessarily ran all new to those upstairs outlets-think the outlet used to run that window a/c is running a few other branches as well-point being when running on high sometimes it blows a breaker.

I am wondering if I can simply run a new dedicated 120 outlet to run just that. I have 3 available spots left in my breaker panel and I am proficient enough to do that-just wondering how I would know if I’m "maxing out" the breaker panel? Not that the a/c unit would use that much….