Great scheme, except that the 13th Amendment had passed out of the Senate before Nevada became a state. And Lincoln was narrowly reelected with 10 times the electoral votes of his opponent.
Thus, Nevada, with a population less than required for statehood by the Northwest Ordinance, entered the union as the 36th state.
The Northwest Ordinance outlined the requirements for a territory to be admitted as a state under the Articles of Confederation. The Constitution replaced the Articles and, as you might know, does not lay out a population requirement for statehood. Arkansas, Michigan, Iowa, Oregon, Wisconsin all were admitted with populations less than 50,000.
Here is a link to the story behind Nevada statehood as told by Charles Dana, Assistant Secretary of War under Lincoln: Link