Rub the beef chuck roast down on all the sides with the seasonings making sure it is all covered.
Place roast inside of slow cooker.
Place onions and peppers on top of roast. Pour salsa on top of everything.
Cook on low heat for 8-10 hours.
Remove roast and shred with 2 forks.
Preheat broiler on oven.
Spray a large baking sheet with non-stick cooking spray and spread shredded beef out on it.
Pour 1/3-2/3 cup of the liquid left in the slow cooker on top of the shredded beef.
Place beef under the broiler for 2-4 minutes or until the ends start to brown and turn crispy (it will happen fast, so watch it carefully!). Remove beef from oven and serve on top of tortillas with your favorite toppings. You can also use it on top of nachos, salads, or any way you want to eat it!
Notes
To get the flavor you want out of this dish you will want to cook it on low in the slow cooker. But, if you are shorter on time you can give our Instant Pot Carnitas recipe a try too!