CC Ādi 6.37

ācārya gosāñi caitanyera mukhya aṅga
āra eka aṅga tāṅra prabhu nityānanda
Word for word: 
ācārya gosāñi — Advaita Ācārya; caitanyera — of Lord Śrī Caitanya Mahāprabhu; mukhya — primary; aṅga — part; āra — another; eka — one; aṅga — part; tāṅra — of Lord Caitanya Mahāprabhu; prabhu nityānanda — Lord Nityānanda.
Translation: 
Śrī Advaita Ācārya is a principal limb of Lord Caitanya. Another limb of the Lord is Nityānanda Prabhu.