Short answer: No.  Paints specifically made for cabinets have hardeners in them, so your kitchen cabinets do not need to be sealed with a topcoat.

kitchen cabinet
topcoat not needed

Now, if you’re putting any specialty finishes on your cabinets, those cabinets will need to be sealed with a topcoat…meaning, if you added powder glazing or distressing (sanding, like the edges, for a vintage “aged” look) you definitely need to topcoat (or clear coat, same thing – little different working) to seal in that finish.

kitchen cabinet with glaze
topcoat needed
kitchen cabinet with powder glaze
you HAVE to topcoat powder glaze!

 And I always recommend that the clear coat is by the same manufacturer as your paint, and that they are made for cabinet painting.