To upload your podcast to Spotify you need to make an one time connection with Spotify for Podcasters.
This is an one time thing, and after completing it Spotify will automatically list your new episodes that you upload on Nightcast.
You can find a detailed guide here, but the steps are:
- Make sure you have a normal Spotify account (I assume you are already using the Spotify app on your phone)
- Publish at least one episode and add cover artwork to your podcast
- Login to Spotify for Podcasters
- Click “Add or claim your podcast” on the menu up left
- Add the RSS feed link you can find on the “Podcast Info” page on Nightcast’s dashboard
- Enter the 8 digit code Spotify emails you
- Wait for a few hours