Brush the steak, green pepper, and onion slices with olive oil and season with kosher salt, pepper, and steak seasoning.
Preheat the grill to medium high heat for a few minutes. Put the steak, green pepper, and onion slices on the grill. The steak will grill 6 to 8 minutes total, flipping halfway through. The veggies will grill a few more minutes than the steak, turning them a few times on the grill.
Let the steak and veggies cool and chop them up into smaller pieces, removing the seeds and stem from the pepper.
Brush more olive oil in a 9×13 casserole dish and add a few spoonfuls of enchilada sauce, spread evenly.
Put some of the enchilada sauce in a bowl. Dip each corn tortilla in the sauce, add some cheese and some of the steak veggie mix. Roll them and place seam side down in the casserole dish, arranging them so they all fit. They are delicate, but if one tears it's ok.
Add any leftover steak veggie filling over top, the rest of the enchilada sauce, and heavy cream. Top with remaining cheese and sprinkle more kosher salt, pepper, and steak seasoning over top.
Bake in a 375 degree oven for 25 to 30 minutes.