Isaac Lea Nicholson (January 18, 1844 – October 29, 1906) was an American Episcopal prelate.

He was educated at St Timothy's Hall in Catonsville, Maryland, after which he entered his father's banking firm.

He was ordained priest on September 22, 1872, by Coadjutor Bishop Pinkney, in St Paul's Church, Baltimore.

He was appointed curate at St Paul's Church, Baltimore, where he stayed till 1875.

Nicholson's consecration took place in Saint Mark's Church, Philadelphia on October 28, 1891.