Cook noodles according to package instructions. Drain, rinse thoroughly (or they’ll stick together!), and set aside.
Meanwhile, make peanut sauce by whisking all ingredients together in a large bowl until smooth. Trust me on the large bowl thing - you gotta whisk hard and it’ll slosh everywhere. It’ll look watery and a little lumpy - no worries, it’ll become thick and smooth when you toss it in the hot skillet.
In a large (preferably 12”) nonstick skillet, warm oil over medium heat. Add vegetables and stir fry for two minutes. Add chicken and season chicken and veggies with salt. Cook until chicken is almost cooked through and vegetables are tender. Add garlic and continue stir frying for 30 seconds.
Turn temperature down to low. Add noodles and sauce and use tongs to toss until sauce has thickened and everything is evenly coated, 2 to 3 minutes. Garnish as desired.