Features Hook after successfull import I wrote a feature module that contains content types and test nodes. After importing those nodes, a certain cache has to be rebuild.

Both hooks I know (hook_install() and hook_enable()) are called before the import happens.
Is there any hook that is executed only once after the feature import is done?
It depends on how the nodes are imported really. You should be able to use hook_modules_enabled which is the last hook invoked when a module is installed and enabled. You might need to tweak your module weight to make sure it's invoked after the import of the nodes.