Preheat oven to 400F. Toss sweet potato cubes with olive oil and a pinch of salt. Roast for 25 minutes until tender.
In a skillet over medium heat, brown the ground beef. Drain excess fat, add taco seasoning and 1/4 cup of water, and simmer for 3 minutes.
In a bowl, mix corn, black beans, mayonnaise, sour cream, lime juice, Tajin, and cotija cheese to make the creamy corn salad.
Assemble the bowls by dividing the sweet potatoes and ground beef equally. Top with the creamy corn salad, sliced avocado, jalapeno, and fresh cilantro.