Heat skillet (or multi-cooker) to medium high heat
Melt 1 tablespoon butter with 1 tablespoon olive oil
Season chicken with garlic powder, salt and pepper and cook on each side until lightly browned (about 3-4 minutes)
Transfer chicken to slow cooker
Add cans of tomatoes/tomato sauce, Italian seasoning and remaining two tablespoons of butter
Cover and cook on high for 3-4 hours or low for 6-8 until chicken is cooked through (reduce time if using tenders 2-3 hours on high or 4-6 on low)
Taste sauce and add more seasonings if desired
Spiralize zucchini and add to slow cooker
Return cover and let cook in sauce until softened, about 10-15 minutes
Garnish with fresh slivered basil
Notes
Here is the spiralizer I use. You could also serve with pasta or with sliced sautéed zucchini.
If the sauce is too acidic for your liking, you can stir in a couple of tablespoons of cream or milk.
I've made this with and without the addition of the Italian seasoning and like both versions, but possibly prefer the one without because I LOVE tomato flavors.