Karki, 73, will be the first woman to lead the impoverished Himalayan nation after a deal was reached with the protest leaders for her to be sworn in.
The agreement between the president and the protest leaders was reached after days of consultations. Legal experts were also involved.
Parliament is expected to be dissolved shortly.
Karki is widely regarded as a person of clean image, and is being supported by student leaders from the so-called "Gen Z" to lead the interim government.