Hey Jakewh, I believe you are getting this error because the amount you have staked is less than the minimum nominator bond (it was increased to 250 DOT a few months ago).
Try going to the staking dashboard’s nominate page and click “Stop”. Go ahead and
submit the chill extrinsic, this may resolve your issue.
Based on that error message, you likely need to chill first (I understand that the error message is not very helpful…). You can then fast-unstake if you haven’t received rewards for the last 28 eras.