In Thor (the movie), we see Thor (the character) pin Loki (the trickster) to the ground using Mjölnir (the hammer). (superfluous parenthetical comment here).
In the Avengers, we see that the Hulk is unable to lift Mjölnir.
In this instance, Hulk's hand should be trapped under the hammer, and yet he is able to let go. This could be similar to how Stark trapped the Hulk in a cage in Age of Ultron, and Hulk dug his way out from under it.
If Thor placed Mjölnir on the Hulk's chest, would it incapacitate him to similar to what was done to Loki?
Note: In an alternate universe, we might say it was adhered to his chest using Toad's spit, and that a time traveling robot placed it there.