There are multiple origins and meanings for the name Nika:
1. Ancient Greek name (Νίκα) meaning - "victory; victorious; goddess of victory; epithet of Athena", see the name Nike
2. Hebrew name (נִיקָה) meaning - "clean, cleanse"
3. Mistakenly considered by some as a form of the name Veronika/Veronica - "girl who brings victory".