is there an ipod that has bluetooth/wireless for running

The iPod nano's Bluetooth is for connecting headphones (and for input from some sensor devices). The user guide

https://manuals.info.apple.com/MANUALS/1000/MA1624/en_US/iPod_nano_2015_user_gui de.pdf

has info about connecting Bluetooth headphones on page 53. iPod nano is small and light.

If you own an iPhone (5 or later), Apple Watch can also connect to Bluetooth headphones. You need the iPhone to use an Apple Watch, but the Apple Watch also operates by itself when doing things like running

Listen to music on your Apple Watch - Apple Support

What do you mean by "wireless"...?

Both iPod nano and iPod touch have built-in Bluetooth. And Bluetooth is a type of "wireless." WiFi is also a type of wireless. iPod touch has WiFi; iPod nano does not. Having WiFi is not that useful for running (during the run).

The other type of "wireless" is cellular, which (along with a wireless data service) is needed for GPS. No iPod has GPS functions. iPhone does; there's a new iPhone (SE) that's close to the same size and weight as iPod touch. GPS is useful for running.

If you own an iPhone (5 or later), the most sophisticated "iPod" for running is Apple Watch. It has Bluetooth and WiFi (but not cellular). Otherwise, the best (actual) iPod for running is iPod nano, which is what I use to track my runs (older 5th gen model). Both iPod nano and Apple Watch use motion-based tracking for runs, not GPS. After the run, they both sync recorded workout data. iPod nano syncs with your computer running iTunes. Apple Watch syncs with your iPhone.

Some runners take their iPhone along, which allows GPS tracking for the run.

What do you want Bluetooth to do, as it relates to running?