St. Nicholas' Chapel (German: Nikolaikapelle) is a former Roman Catholic parish church in the city of Hildesheim in Lower Saxony, Germany. It is dedicated to Saint Nicholas and is located in the southern part of the old city centre, opposite St. Godehard.
Saint Nicolas' Chapel was built in a Romanesque style in the 12th century at the same time as the monastery of Saint Godehard was built opposite. It was consecrated by Heinrich von Minden, the bishop of Minden, in 1146.Bernard of Hildesheim (1130–53), the then bishop of Hildesheim was not able to consecrate it himself as he had become blind. Saint Nicolai's Chapel was used as a catholic parish church until 1542 when Protestantism was introduced in Hildesheim. Many inhabitants of the city, however, did not become Protestants. Saint Nicolai's Chapel, one of the smallest churches in Hildesheim, was allocated to the Protestants, who actually did not need it. At first, they used it as a stable. The church was not used as such until 1557, and there were plans to demolish it and to use the stones to repair the medieval city wall. As the monks living opposite the chapel in the monastery of St Godehard opposed the plans, St. Nicolai's Chapel was returned to the Catholic Church in 1557, but it was in very bad condition. It was renovated at various times. According to an engraving by Merian dating from 1653, it was an aisleless church with a hip roof and a flèche.
The chapel was used by the monastery until 1803. In that year, it was sold to a private owner after the monastery had been dissolved during the secularization and it was transformed into a residential building.