"Leonard’s integrity and passion as an actor and devotion to his craft helped transport STAR TREK into television history," Nichols, 82, continued. "His vision and heart are bigger than the universe. I will miss him very much and send heartfelt wishes to his family."
Nimoy died Friday morning after battling chronic obstructive pulmonary disease. He went public with his diagnosis in 2014.
Nichols released her statement during an appearance at the 2015 Pensacon, in Pensacola, Florida.
Star Trek costars have said Nimoy repeatedly stood up for them, including Nichols.
Walter Koenig told the Las Vegas Sun last year, "When it came to the attention of the cast that there was a disparity in pay in that George [Takei] and I were getting the same pay but Nichelle was not getting as much, I took it to Leonard and he took it to the front office and they corrected that."
Nimoy confirmed that incident to TrekMovie and added, "There was also the case where George and Nichelle we’re not hired to do their voices in the animated series. I refused to do Spock until they were hired. Mr. Roddenberry started calling me the conscience of Star Trek."