nicholls was consecrated a bishop on february 2, 2008. she served as a suffragan bishop in the anglican diocese of toronto, canada from 2008 to 2016: she was in charge of the trent durham area of the diocese. on february 13, 2016, she was elected coadjutor bishop of the diocese of huron — she was the first woman to be elected a bishop in the diocese — and she automatically succeeded to the role of diocesan bishop of huron on november 1, 2016 upon the retirement of robert bennett.