Complex sentence: Nemtsov has stated that he views Crimea as an integral part of Ukraine and its annexation by the Russian Federation to be illegal, saying the people of Crimea and not Russian legislators should decide in which country they should reside.
Split into simpler sentences: Nemtsov has stated that he views Crimea as an integral part of Ukraine and its annexation by the Russian Federation to be illegal. Nemtsov stated the people of Crimea and not Russian legislators should decide in which country they should reside.