Drain tomatoes well. Add to crock along with beef (yes, uncooked!) and corn. Use a spatula to break up the beef.
In a small bowl mix together all the the seasoning mix spices. Add two tablespoons of the mixture to the taco meat and save the rest in an airtight container to use later
Add water and stir to coat the meat mixture with the seasoning
Cover and cook on low for 5-7 hours or high for 2-3 hours until meat is fully cooked
Right before meal time you will want to shred your cheese for your sauce
Melt the butter over medium high heat and then whisk in the flour. Keep whisking for about 1-2 minutes to let it cook up just a little
Slowly add in the milk while continuing to whisk to avoid any lumps
Keep stirring with a spoon and let it cook and additional 4-5 minutes until it thickens up and will coat the spoon
Remove from heat and stir in cheese until fully melted.
Add about ¾ of a cup of the cheese sauce to your meat and stir everything to combine. Use extra cheese for drizzle, for chips, or save in airtight container in fridge for up to 2 days
Serve with your favorite shells and lettuce and tomato as desired