I substituted a large yellow squash from my garden for the zucchini. It was so delicious!! My husband really loved it too! I made sure not to overcook the chicken during the sauté step. The red onion I used was a little on the larger side, as were the garlic cloves. It tasted very flavorful and the lemon juice made it tangy. I really loved it and it will be a go-to recipe for us. I was surprised by how delicious it was because I was afraid it would be dry and bland after I read the bad reviews.