Season the chicken tenderloins with salt, pepper, garlic powder, and onion powder, and let them marinate.
Sous vide the chicken until cooked through, then cut it into bite-sized pieces.
Make the sauce: dump the tomato sauce, table cream, ketchup, mustard, mushrooms, salt, and pepper into a pot and cook until warmed through and combined.
Add the chicken to the sauce and heat everything together. Serve.
I double all the sauce ingredients because one batch isn't saucy enough. Adapted from this video.