Heat vegetable oil in a large Dutch oven over medium-high heat. Add the squash and onion, and sauté 5 minutes. Add 1 cup water and the next 4 ingredients (1 cup water through chile); cover and cook 5 minutes. Add 1 1/2 cups water, salt, and tomatoes; cover, reduce heat, and simmer 20 minutes. Add the corn and beans; cover and cook 15 minutes. Discard the chile.
The idea here is fine, but more flavor is needed. Skip the water! I left it out entirely and just used 1 cup--no more--of chicken stock. I also chopped an anaheim pepper and sauteed it in with the onion. Used hominy instead of corn--and a whole can of it. Add lime juice, cilantro, and crumbled queso fresco, and you have it. I added just a small salad with sliced oranges and cornbread for a hearty meal.