Pesto in pasta salads

I've misplaced the recipe but we used to make a great pasta recipe - tortellini and cooked chicken and blanched sugar snap peas. We mixed about 1/3 pesto to about 2/3 mayo (it can be light, non-fat or regular - and you can also put in some yogurt or sour cream, if desired). I think we put in a bit of chopped onion, etc. I'm not giving any amounts re the 1/3 to 2/3 -- as this was a party recipe (hope I can find it soon! tho I can probably 'wing it!) and very good. Only problem (and not big) is that it is best not mixed too far in advance - as the dressing sort of disappears if it's been refrigrated, say, overnight.

We've used the 1/3 - 2/3 ratio in other salads (great with tuna!) and in dips/spreads.