Complex sentence: In 1957, after the death of Stalin, Nikita Khrushchev allowed the Chechens to return and the Chechen republic was reinstated in 1958, the authority of the Soviet government gradually eroded.
Split into simpler sentences: In 1957, after the death of Stalin, Nikita Khrushchev allowed the Chechens to return, and the Chechen republic was reinstated in 1958. Afterwards, the authority of the Soviet government gradually eroded.