Heat the frozen veggies in the broth instead of microwave (keeps any remaining water soluble nutrients in the dish, and makes the veggies less wilted imo).
Try different frozen veggies (green beans, carrots, corn, spinach, avocado?).
Most fresh veggies can be sliced or diced into it as well whenever there’s a good price on them, and the taste and texture provides avriety from frozen veggies, but in my experience frozen are usually cheaper. But half a fresh bell pepper can give plenty of good crunch of you add it raw on top. Or thinly sliced or chopped cabbage.
Add one or a half package of drained ready-to-eat beans (packages in water, not dry) for fiber, protein and minerals.
Experiment with different spices and sauces to put on top. Coconut milk, peanut butter, soy sauce, sriracha, sesame oil, crushed tomatoes…anything you’ve got available can go in (but not everything goes well on the same occasion). The more you spice it yourself the less you need to put of any included spice mix, which is mostly salt, while the noodles themselves are usually also mostly salt.