One of my friends gave me this recipe ages ago. She made it for a potluck, and it was really tasty and super easy, so of course I had to have the recipe. I'm not sure where she got the recipe, but I did a quick search, and it's very similar to this one.
If you like your food spicy, which I do, and I think Thai food is supposed to be spicy, you can add some hot chiles. This recipe as it stands is not spicy. I was very tempted to add a few chiles last time I made this, but my husband doesn't like his food too spicy, so I resisted. This chicken really has a great flavor even without the extra spice.
Definitely make sure you use the boneless skinless thighs for this recipe. I wasn't paying close enough attention the first time I made this and used bone-in thighs. The flavor was still really good, but there were some pieces of bone or cartilage or something that had to be picked out of the sauce - not fun. The chicken was definitely cooked, though! I also tried this with boneless breasts once, but the chicken turned out really dry. It doesn't seem like that would be possible, with the slow cooking and the sauce, but it just wasn't right.
While searching, I found another Slow Cooker Thai Chicken recipe that looks interesting. I may try it next time, or at least incorporate the red pepper and onion into this recipe.