Well, its MY name, so I guess I can comment with a small amount of authority? ;)
Its pronounced Nickel-uh. Everyone in the USA will pronounce it Nicole-uh. Everyone in the rest of the world will say it the right way. Lots of people will think its a typo of Nicole.
In Italy its a male name, but in 30 years I have never been mistaken for a boy. If I was, it wouldnt bother me. Obviously since I am an adult, I think it ages fine. I was called Nikki when I was younger and still some today.
While of course no one tells you when they hate your name, I do get a HUGE amount of compliments on it. I absolutely love my name and am very glad I am not a Nicole. Its one of the reasons I have some of my children names that so many people swear will be 'nightmares' for certain reasons (uncommon, unisex, unknown pronunciation) because I actually have one and wouldnt change it to the more common/ easier/ boring version.
My middle name is Jane. I would go with a one syllable name.