Dissolve bouillon in water in small saucepan. Pour 1/2 cup broth into large skillet. Let remaining liquid in saucepan cool.
Bring broth in skillet to boiling. Add chicken and simmer 5 minutes, until no longer pink. Remove chicken and discard excess liquid from skillet.
Stir soy sauce and cornstarch in small bowl with approximately 1/4 cup water until smooth. Stir into broth in sauce pan.
Heat oil in skillet over medium-high heat. Add garlic and ginger; cook 30 seconds, stirring constantly so it won’t burn. Add cabbage, celery, peas, and carrot. Cook, stirring, 1-2 minutes, until heated through.
Stir cornstarch mixture in saucepan; add to skillet. Cook, stirring, 2-3 minutes until slightly thick. Add cooked spaghetti noodles. Top with onion.
If you’d rather not use chicken bouillon, just use the same amount of water called for in the recipe and substitute it with chicken broth. Also, you can use a coleslaw mix for the cabbage instead of shredding your own.