2002 Mercury Mountaineer

Hello all, I have a quick question. I have a 2002 Mercury mountaineer
and I was just told that the timing chain is causing my truck to make a rattling noise and that it needs to be replaced. I am currently in bewtween jobs and I was told that it can be pretty expensive to repair. Any ideas on what I should do? Does it take an experienced mechanic to make this kind of repair or is it something I could do myself? Is is even worth it? Thanks!