Taco Casserole

This recipe is adapted from one I found at The Cozy Cook (https://thecozycook.com/taco-casserole/). The ingredients I used are listed below:

1 small onion
1 lb ground turkey
2 tablespoons taco seasoning
3/4 cup water
1 (16oz) can refried beans
1 cup sour cream
2 cups shredded sharp Cheddar cheese
1 (14.5oz) can diced tomatoes, drained
Dollops of store-bought salsa
2 (2.25oz) cans sliced olives, drained
1 jalapeno pepper, sliced, ribs and seeds removed
Crushed tortilla chips