Pasta Insert for stockpot
It is a catch 22 question.
Yes, if there is sufficent of elevation above the water, with a sufficent quanity of water. Use a 3rd basket or false bottom in the insert.
No, if the steamed food item cannot be raised above the water or insufficient water level to create sufficient steam. Don't try it with the insert only if it hangs too deep.
Personally, l prefer separate steaming/pasta inserts. Steaming is best with a fair amount of clearance to give you options to add a fair quantity of water. Pasta is best with low clearance, so that you can get a fair 'height' to get evenly cooked long noodles. I had a Lagostina that had an in-between height and I found it to be a little low for steaming and a little high for pasta. I've replaced it with a Cuisinart with two separate inserts and I prefer the results.
That said, as long as you can fit enough water under the pasta insert -- it'll work just fine.