Can I use chicken thighs instead of breasts?
Absolutely. Boneless, skinless thighs are even more forgiving and stay super tender. They often taste best when cooked a little longer than breasts so the connective tissue has time to relax, so do not be afraid of the longer end of the time range. For ideal texture, many people love thighs closer to 175 to 190°F (still safe at 165°F, just different texture).
Will the citrus make the chicken tough?
Generally, no. Citrus can firm up the outer texture a bit, especially if you overcook, but in a slow cooker with plenty of liquid it usually stays juicy. The key is to start checking early and pull breasts when they hit 165°F.
Can I cook this on Low or High?
Yes. Cook on Low for 4 to 5 hours or High for 2 to 3 hours, depending on thickness and your slow cooker. If your chicken breasts are small or thin, they may be done earlier, so start checking around the 3-hour mark on Low or the 2-hour mark on High.
Do I have to thicken the sauce?
Nope. You can serve it as a brothy, light cooking liquid. But thickening it takes 3 minutes and makes it feel like a real sauce, so I strongly recommend it.
Is this spicy?
Not unless you make it spicy. Add red pepper flakes, sliced jalapeño, or a spoonful of chili crisp at the end if you want heat.
What can I do if the sauce tastes bitter?
That is usually from too much citrus pith or simmering a lot of peel. Next time, use thin slices with minimal white pith and do not let slices sit directly on top of the chicken the whole cook. To fix it now, stir in 1 to 2 teaspoons honey or a splash of orange juice.