I almost never noose chucks. If they make it into the crack there is no pulling them out, and they would be left with a noose around their neck. So, unless you are really sure, you can get them noosed and airborne before they can get into the crack, I wouldn't try it.
When they hide, you've basically got a couple of options. Sometimes they hide under a flippable rock and you can flip it and catch them. It helps if you have at least two people here, one to flip and one to grab.
The other option, if the rock isn't flippable is to induce them to back out. This is best accomplished by tapping them repeatedly on the nose with a small stick. This is how I got mine. When Gracie dove into the crack, I was able to slip a stick in bellow her so that she couldn't go deeper. I then had my friend put his hand over the back of the crack. It took about 15 miutes of gently tapping and she gradually backed into his hand thinking it was an extension of the rock.
There is no pulling them out. If you flip, be sure to return the rock to its original position. I would also urge you to not break apart the rocks / permanently damage the hiding spot as this would ruin it for future chucks. If you get one in a crack, and there is no reaching the nose, either move onto another spot, or back off and wait and watch out of sight. Depending on how badly you traumatized the chuck in your initial extraction attempt, it cold re-emerge in a matter of minutes.
-Alice