Can I use Arduino nano's power straight for the micro motors or do I need to use drivers for a drone?
The Atmega328p datasheet states that you can draw a maximum of 40mA per I/O pin, with a maximum of 200mA for the full device (you can drive around 4 I/O pins at max current, since the processor itself will still draw some additional current).  If you need more current than that, you'll need to use a MOSFET (for single direction on/off) or an H-bridge (for two direction on/off), or an ESC module (for brushless motors).

datasheet, see page 313