In a large skillet over medium heat, heat oil.
Add stir fry mix and cook until tender, about 5 minutes.
If you precook your ground beef, skip this step. Remove veggies from the pan. Add ground beef, season with salt and pepper, and cook until no longer pink, 5 minutes more. Drain fat and return vegetables back to the skillet.
Make sauce: Whisk together soy sauce, brown sugar, apple cider vinegar, chili sauce (optional), and garlic.
In a separate saucepan, bring water to a boil. Add ramen noodles and cook until tender, about 2 minutes.
Drain noodles, then add to the veggie and beef skillet.
Pour sauce over your veggie, noodles, & beef.
Toss until completely combined.
Taste and season with more salt and pepper, if necessary.