Hello! You can absolutely make a wonderful stir fry sauce with the ingredients you already have in your kitchen, so there is no need to spend money on a new bottle of rice vinegar.
Out of the items in your fridge, apple cider vinegar is your best option. Rice vinegar is known for having a mild, slightly sweet taste with less sharp acidity than distilled white vinegar. Apple cider vinegar shares a very similar gentle acidity and subtle fruity note, making it an ideal 1:1 replacement. To match the flavor profile even more closely, you can add roughly 1/4 teaspoon of sugar for every 1 tablespoon of apple cider vinegar.
If you choose to use plain white vinegar, keep in mind that it is much sharper and more acidic. To substitute 1 tablespoon of rice vinegar, I recommend using 3/4 tablespoon of white vinegar combined with 1/4 tablespoon of water and 1/4 teaspoon of sugar. Diluting it slightly prevents the harsh acidity from overpowering the rest of your chicken and vegetable stir fry.
Lemon juice can also be used in a 1:1 ratio if needed, but it will introduce a distinct citrus flavor to your sauce rather than the traditional fermented tang of vinegar. For the best balance of flavor tonight, stick with the apple cider vinegar and a tiny pinch of sugar.