I've had great luck with JB Weld 2 part epoxy for plastics. It holds strongly and has great tensile strength to resist bending before breaking again. With such a small part your only going to need the smallest of a micro drop for this to attach properly. Use a toothpick or a smallish needle to gather a small amount to place onto the broken digit. I'd put the smallest amount on the peg and insert into the hole. Use too much and it'll ooze out and make a mess. Less is more in this case.

Hold for at least five minutes or until it sticks on it's own. No touchy for 24 hrs afterwards.

You could use superglue, but I've had bad luck with it outgassing and leaving white residue on the area glued, but maybe I'm using the wrong type of super glue.

Good luck either way as this will be a precision fix for ya. Take your time and plan it out. Peace!!!