Nichols went overseas in November 1581 to enroll at the Douai College (located in Rheims at the time); which was a seminary for English Catholic priests.
In May 1589 he was arrested at the Catherine Wheel Inn, opposite St Mary Magdalen Church in Oxford, with another priest Richard Yaxley, and two laymen, Humphrey Pritchard and Thomas Belson.
The men were accused of treason in accordance to a statute issued by Parliament following the Papal bull issued by Pope Pius V. The four men were ultimately sent to Bridewell Prison in London, where Nichols and Yaxley were hung from their hands for up to fifteen hours to make them betray their faith, but without any success.
Nichols and his fellow prisoners were tried under the recent statute imposing the death sentence on any Englishman ordained abroad who entered England and on anyone helping such a person.
[2][3] In 1987, Nichols and the three other prisoners were among eighty-five martyrs of England and Wales to be beatified by Pope John Paul II.