Depending on what aspects of chiptunes you care about, the Polyend Tracker Mini (https://polyend.com/tracker-mini/) might be right. It's less like a portable hardware version of Bintracker and more like a portable hardware version of Renoise. So it's a hardware tracker device, and you could load up some lofi square and saw wave looping samples and some looping noise samples and make music with the tracker that many would consider chiptunes, but you don't get the chip emulation that Bintracker has.

That's pretty cool, despite the price point, especially if it outputs 8bit tunes.

You could get a MIDI controller (keyboard with MIDI output but not sound generation capabilities) and connect it to a suitable MIDI synthesizer. There are many MIDI synths available with real or emulated chip sounds.

I always wondered if you can use midi capable pianos to play chiptunes, even emulated tunes if not actual 8bit.