Breeze actually doesn't support the LN address required for nostr. Typically recommend getalby.com or walletofsatoshi.com Once you have one of those you'd drop the LN address (looks like an email address) into your profile

Yes, Breez doesn't provide LN addresses. Like dan says, try getalby, wos or even @LightningTipBot on Telegram (there are a bunch of other services that provide addresses though), which is quite fun because you get zap notifications