How to connect both MicroSD module and MPU9235 power in an arduino
VIN takes 6-12v and it sends it through the on board regulator - so that is the best way to power the nano.  

If you take a wire from the 3v3 pin and split it (solder two wires to one) then you will have two 3v3 feeds to wire to your two devices.  This will be the same as you have to do for the Gnd connections, back to the Nano.

Does that make sense? (if not I'll try and draw you something).