"Might" = there is a chance of something happening but its more 50/50
"Could" = something can happen if others are willing to.
Might Examples:
1. "I might be able to visit you this weekend, if I am able to get time off work."
2. "According to the weather app, It might rain today."
Could examples:
1. "Could you pass me my phone?"
2. "I could go out tonight, but I'm still not sure if I want to or not."
3. "We could go see a movie, If you're up for it."
I hope this helps! Feel free to ask me if you need any clarification!