@checheftaxi
There must be something going on in her life that is making her have these attitudes.
If the family dynamic is how you describe it, which has always been favourable it can mean influences from outside the house may be playing a big part right now.
Do what you've always done and show her support and understanding. Tell her that if something is wrong in her "busy life" that she can approach you at any time to discuss it but make it clear it isn't a reason to be spoken badly. Tell her how it makes you feel when she speaks to you like that, and how she may have changed. Make her think if this is how she wants to be perceived by others. If this behaviour is only towards you, keep insisting on discussing what's wrong. Not excessively but with time, and let her blow steam in her room, but never towards you.
Put your foot down, no yelling no threats, no condescending tones, just that you won't tolerate it, if you weren't disrespectful towards her she has no reason to disrespect you and that's the main rule. Death stare, serious gaze and disengage. You'll let her reflect on it alone. But let her always come to you and greet with a smile. Would you tell me what's on your mind? Is everything ok? The way you speak to me is hurtful, I am upset by this.
How does she act with others, with sibling? Other family? Friends?
What is going on in her life, why is it busy? Trouble with studies? Boyfriends?
There must be something. Obviously the behaviour won't go away overnight, but you must have picked up the first time the dynamic started to swift away, but be firm.
Don't ignore disrespect, and by this I don't mean you yell back or say something mean in return, just make sure she understands that you are hurt and things need to change.
And if she is old enough to do her chores, you may stop doing them reasonably to show her things need to be done and will pile up if not done. I know that every child reacts differently but worth a try on the chore part. They should know by now chores are part of life and if she has seen you for many years do things every day, she will know there is no escape them, when she moves there will be no mother doing them for her either.