Preheat oven to 400 degrees F. Line with parchment paper. Place zucchini on the baking sheet, cut side up, season with salt and pepper.
In a large saute pan, heat the olive oil over medium-high. Add beef and cook, breaking up into small pieces with a wooden spoon until no pink remains, about 3 minutes. Drain off fat. Season with salt and pepper to taste and stir in the taco seasoning. Transfer to a large bowl.
In the same saute pan, add in the beans, corn, salsa, and tomatoes; mix to combine and warm through. Season with a little salt and pepper. Transfer to the bowl with the beef, along with the scallions.
Fill zucchini shells with the beef mixture. Bake for about 20 minutes, until zucchini is tender.
Sprinkle with the Monterey Jack cheese and place back in the oven for another 5 minutes until melted.
Serve immediately and enjoy!
The filling can be made the day before, just warm it up a bit before stuffing the squash.
The filling is so delicious and substantial on its own, if you want to ditch the zucchini entirely. Or serve in lettuce cups!
Nutritional information given is an automatic calculation and can vary based on the exact products you use and any changes you make to the recipe. If these numbers are very important to you, I would recommend calculating them yourself.