Please don't "snip her" on the nose for hissing at you or scratching you. I don't know what the problem is, but blow a short, sharp puff of air into her face. Physical correction doesn't work for cats and will make her distrust you and become hissier in the long run.
We had a kitty that didn't want a whole lot to do with us for her two years, then slowly came around to enjoy a few pets and her purr was so slight you couldn't hear it, you could only feel it. She's 5 now and climbs on our laps and purrs up a storm.
If I were you, I'd take her to the vet for a check-up and start working with her like a kitty that needs to be socialized. I'd buy Feliway, and use it around your home (avoid anywhere near litter boxes and scratching posts). I'd consider getting Bach's Rescue Remedy and putting a few drops in her water dish when you clean it every day and dab it behind her ears, at the base of her tail, and under her chin.
http://www.bachflower.com/Pets.htm
I'd get a couple of t-shirts really good and sweaty, and I'd put one under her food dish. I'd put one in her favorite place to sleep, and I'd give her a lot of play time with a wand toy - at the end of a play session, I'd put treats down on one for her.
Apart from the daily play time, I'd ignore her completely for the next few weeks. Don't look her in the eyes - this is a sign of aggression. Don't walk toward her - avoid her. Walk around her.
Does she have much vertical space? I'd provide some for her. A cat tree, a window seat, whatever you can.
How old was she when she was taken from her mom? I wonder if part of the problem is that she never learned kitty manners? Or that you've tried to train her by lightly bopping her on the nose?
