There is a risk - if you're AA flight is delayed you might miss the LA flight.

I don't think you can check your bags through - you will have to clear customs and immigration in SCL as you arrive, and recheck your bags for the domestic flight. They do close the check in on the advertised time. If you are too late you might not be allowed to check your bags. I have found that out to my cost.

I'm sure others will be around to advise on Chilean immigration waiting times at that time of the morning - I've never arrived that early in SCL.