Nichols received a Bachelor of Arts in 1992 from Dartmouth College, where he majored in philosophy and graduated with high honors.

President Trump nominated Nichols to the seat vacated by Richard W. Roberts, who assumed senior status on March 16, 2016.

[16][17][18] In March 2022, Nichols ruled that Garret Miller, one of the defendants criminally charged in connection with the 2021 U. S. Capitol attack, could not be charged with obstructing Congress's certification of the 2020 presidential election without a showing that Miller had tampered with official documents or records as part of the attack.

[19][20] Nichols's ruling is contrary to those of all seven other U.S. District Court judges who had considered the same issue, and may affect up to 275 similar criminal prosecutions.

[21][22] On Sunday, September 27, 2020, Judge Nichols, granting in part the motion of plaintiffs TikTok and ByteDance, issued a preliminary injunction partially enjoining (i.e., temporarily stopping) the Department of Commerce's implementation of President Donald Trump's August 6, 2020, executive order prohibiting certain transactions related to TikTok.

The portion of the prohibition that Nichols enjoined would have barred Apple and Google from offering TikTok in their app stores, and would have taken effect just before midnight that night.

[23] On December 7, 2020, Judge Nichols granted a second preliminary injunction requested by TikTok and ByteBance, enjoining the remainder of the Commerce Department's implementation of that executive order.

[27] The state, through its attorney general and co-defendant Letitia James, promptly asked Nichols to dismiss the lawsuit or transfer it to a federal court in New York, on the ground that it cannot be maintained against them where the defendants neither reside nor act.