Nonbinary & gnc folks can be butch or femme if they feel those labels fit. These terms are not exclusive to cis lesbians.
Some cis lesbians insist this is not possible, that you can only be butch or femme if you are a woman. However, in doing so they deny the lived experience of me, my partner, and many others.
We know what we are and how we feel, and we are connected to a long and rich history of gender nonconformity. You can tell us to stop using these labels, but we won't. These words express a fundamental truth about us, and we have as much right as any cis woman to use them.