Can the nano be flown indoors?  Absolutely

Can it be flown indoors inside a very small space?  Absolutely, IF you are an experienced pilot.

Since you are brand new to CP helis...IF you go the nano route, do your first flights/learning outside.  You and your heli will be grateful for this advice.

Once you get the hang of hovering tail in.  Then you could try inside.

The nano is like a hummingbird on crack if you let it be.  And someone brand new that will over correct on the sticks WILL crash it.  The good thing is that its a tough heli and if you crash you probably wont break anything, and if you do it will be inexpensive to repair.

If you constantly are crashing it into hard surfaces likes ,walls or furniture...it will break more often and you will be repairing it more than flying it.  At least if you are flying it outside and crash it on the grass...you most likely will pick it up from the ground and be right back to flying it with no repair work needed.