Meaning and local context
In Texas, “might could” means Might be able to or perhaps could. A Southern double-modal construction heard in Texas and nearby regions.
Example in context
A local example is “I might could help tomorrow.” In plain English, that means “I may be able to help tomorrow.”
I might could help tomorrow.
I may be able to help tomorrow.
How to interpret it
The surrounding sentence is important when interpreting “might could”. Use the regional sense above when the situation matches the example instead of relying on the word or phrase in isolation.
Tone and caution
It is regional grammar, not careless repetition. Because this is informal regional language, tone and situation should guide whether you use “might could” yourself or simply recognise it when someone else uses it.