What does "catch it on the chin" mean?
Solution 1:
While it is true that expressions like having a chin are used in boxing to express "having the ability to absorb punches when you get hit with a big shot and stay standing", my understanding of "catch it on the chin" is that it means to be struck a severe blow and not receive it well. At boxing.isport.com boxers are advised "Tuck your chin to your front shoulder to limit the effect of punches landed on your head", and at heavyfists.com, "If you think you have a weak chin or a glass jaw, bulk up your neck." Even so, letting a punch get to your head is a failure of defense, and to take a hit on the chin is to risk being knocked out. The idea is to catch punches on your gloves, on your elbows, not on your chin, because rapid head motion bumps the brain into the skull, which is the usual knockout mechanism.
As mentioned in a comment, thefreedictionary.com lists take it on the chin:
take it on the chin and take it on the nose
1. Lit. to stand up to something adverse, such as criticism. (Fig. on taking a direct punch to the head in boxing.) They laid some blunt criticism on him, but he took it on the chin. I knew he could take it on the nose.
2. Fig. to receive the full brunt of something. Why do I have to take it on the chin for something I didn't do? If you did it, you have to learn to take it on the chin.
However, take it on the chin is not the same as catch it on the chin, which as I explained above indicates a failure of defense.
Solution 2:
undaunted; not cowed down by; cf. "face it".
also, take it on the chin (see on idioms.thefreedictionary.com)
Solution 3:
If a fighter takes a hit on the chin, it will whip his head around because of the leverage. It other words, it will be a very effective hit. Thus, in general, taking something on the chin is not a good thing. It means you take the full hit of it. On the other hand, if you willingly take something on the chin, it's a brave thing to do. As Kris says, you face it without turning away.