I am the beneficiary of my mother's estate who's deceased now. My niece was named executor of my mother's estate can she have me removed or evicted ?

If you are the only beneficiary, you might wind up with the house.  But it is the executor's duty to gather the assets, pay the debts and distribute what is left according to the Will.  The house may have to be sold to pay the debts.  If so and if you do not leave voluntarily, you could be evicted.