More null checks

tree/.local/nu/tailscale.nu

@@ -31,10 +31,15 @@ def "tailscale peer" [
 	})
 
 	if $hostname == null {
-		$peers
-	} else {
-		$peers | where host == $hostname | first | get $get_field
+		return $peers
 	}
+
+	let peers = ($peers | where host == $hostname)
+	if ($peers | is-empty) {
+		return null
+	}
+
+	$peers | first | get $get_field
 }
 
 # SSH to a tailscale peer