Wash your hands and clean your preparation area. Rinse any fresh vegetables under cool running water before chopping. Wash the tops of cans before opening.
Place the chicken breast, diced tomatoes, taco seasoning, onion, and water into the slow cooker. Cook on high for 4 hours or low for 6 hours. Ensure chicken reaches the proper internal temperature of 165* degrees.
In a medium-size skillet heat the olive oil over medium heat. Add the corn and jalapeno peppers to the skillet. Let cook without moving for a couple of minutes to slightly scorch the corn. Add the chili powder and cook until the corn is cooked through and to your desired level of scorched. Remove from heat and add the lime juice and cilantro.
Remove the chicken from the slow cooker and shred for assembly.
To assemble the tacos gather your tortillas and add the chicken, roasted corn, and top with the cotija cheese.