Miller joined the Swans in January 2024 from third-tier side Gwalia United.
The versatile player arrived at the club alongside Lauren Davies and Caitlin Williams, making the move from the English league setup.
The 21-year-old brought significant experience to the Swans, having previously spent time with Brighton & Hove Albion and Durham.
Miller also has international pedigree, having previously captained Wales at under-19 level.