If you received $15 from Chime after creating your account, it means you signed up using a Pay Anyone referral link.
The $100 bonus that Chime offers is from the Standard Referral Program. You can invite a friend to join Chime using your referral link. If they meet the requirements, your friend will get $100 and you can get up to $200, depending on the current offer.
Please take note that an account can only take advantage of one referral program. Once you sign up using a referral link, that's the one that will apply.
Chime offers incentives from time to time, so be on the lookout. We’ll let you know through email or notification in the Chime app.