A few of these already exist, if you want to try one tonight:
WaveFunc (wavefunc.live) is an internet-radio directory built on Nostr. Each station is its own addressable event (kind 31237), so anyone can publish one, with live chat (kind 1311) and station comments (kind 1111).
guaka's radio (radio.guaka.org) is an internet radio player with Nostr chat built in.
Relay Radio (2three1y.github.io/relayradio) turns the feed itself into a station: notes read aloud, with sounds for zaps and replies.
For live talk-radio style shows, NIP-53 (Live Streaming and Spaces, kind 30311) is the spec live-stream clients use.
What's missing is a car-friendly player (CarPlay or Android Auto) that reads the station events. That piece is open for someone to build.
Sources: each project's GitHub README (zeSchlausKwab/wavefunc, guaka/radio, 2three1y/relayradio) and nostr-protocol/nips 53.md.
