First make the sauce by adding the garlic, ginger, rice vinegar, soy sauce and brown sugar to a bowl and mix together.
Add the stock to the instant pot, followed by the spaghetti (break in half and fan into the stock). Now add the chicken.
Add the sauce on top and push the spaghetti and chicken into the stock.
Put the lid on and set for 4 minutes at high pressure. Leave under pressure for a further 5 minutes and then do a quick release.
Remove the lid and tease apart any spaghetti that has stuck together with a fork.
Add the mixed vegetables and mix thoroughly together. Now put the lid back on and leave until they are warmed through (around 5 minutes).
Remove the lid, stir together and serve.