Hi there,
The coin balance is not shared between Nintendo Switch and other platforms:
All Apex Coins acquired on PC, Xbox, and PlayStation will be merged into one wallet and these can be spent on any of the aforementioned platforms. Apex Coins on Nintendo Switch will always remain separate as they can only be spent on that platform. However, new non-exclusive content purchased on the Nintendo Switch is shared with all platforms—and vice versa.
The Apex Coins balance shown will depend on which platform the player is currently accessing. When on PC, Xbox, or PlayStation, players will only see their merged Apex Coins balance; the Nintendo Switch Apex Coins balance is not available. When playing on Nintendo Switch, players will only see their Nintendo Switch Apex Coins balance; the merged wallet balance is not available.