Many adhesives will work on plastics.
With toys and things like this you first want to consider the age of people handling them. If a child will chew on it, be sure to avoid resins that are known to be toxic.
Avoid superglue and low-surface-tension adhesives. "low surface tension" means that it slips down into cracks easy. Sometimes people call this a "thin" liquid. It causes the liquid to 'wet' surfaces easily.. meaning that it runs into new areas.
You want to avoid superglue because it is more likely to 'leak' outside of the surfaces that you want to adhere. It does this because it 'wets' surfaces easily. When superglue does this, it can cause two main issues:
- superglue is usually shiny when dry, and will probably be a different shininess than the thing you repaired. This makes the glue very visible when you look at the action figure, and it will reduce your enjoyment of it. If you're trying to sell the action figure, it will lower its value.
- the thing that is being repaired may stick to the table or paper towel where you left it to dry / set.
Use an epoxy that is thicker, this will prevent the wetting. Some epoxies come with a thickening agent. Do not add your own 'thickening agent' thinking that it will get the results you want — thickening agents that come with the kit have specially formulated chemistry. You may only be left with a bigger mess.
Test on other plastics in order to confirm it will work the way you want. You can always take a scrap from something you're throwing out, or find around a trash site — break it, and then try to repair it.