Heat a deep skillet. Saute onions with a bit of olive oil and butter.
Place the chicken pieces in the pan once onions start to become translucent. Cover and cook the chicken over medium heat, gently stirring and turning the chicken every 15 minutes or so, until the chicken is tender enough.
Keep the heat adjusted so that the chicken doesn’t scorch.
Add the jalapeño peppers and simmer gently for 5 to 10 minutes.
Reduce the heat to low, stir in Greek yogurt or cream.
Remove the pan from heat just before it starts to simmer. Season with salt and pepper.