Born into a Lithuanian peasant family, Nastopka graduated from Vilnius Military School and served in the Imperial Russian Army.

During World War I, he was promoted to lieutenant colonel (podpolkovnik) and commanded the 178th Venden Infantry Regiment [ru].

During the Lithuanian–Soviet War, he commanded the Separate Brigade that carried out the first organized Lithuanian offensive in April 1919 and the Panevėžys Group which pushed the Soviets across Daugava by August 1919.

Despite his father's death in 1894,[1] Nastopka completed six classes at the real school in Bauska and passed his gymnasium examination in Vilnius in 1902.

[4] The Bolshevik government wanted to send the battalion to suppress the Polish 1st Corps in Russia commanded by Józef Dowbor-Muśnicki.

[4] Nastopka returned to Lithuania in November 1918 and voluntarily joined the newly established Lithuanian Army.

[8] This promotion occurred just as the West Russian Volunteer Army (also known as Bermontians) intensified their attacks against Lithuania.

The 13th Wilno Uhlan Regiment (a Polish cavalry unit) manoeuvred behind the 1st Division's positions and captured its command, including Nastopka, on October 21.

He was army's inspector from July 1921 to October 1923 when he became officer of special affairs reporting to the Chief Commander.

[1] His war-time spine injury caused him continuous health issues, including painful episodes of paralysis.