Ayyā Nimmalā Bhikkhunī began her journey into Buddhist monasticism by serving as a steward first at Birken Forest Monastery and later at Tisarana Buddhist Monastery where she was guided by dedicated teachers including Ajahn Viradhammo, Ajahn Sona and Ajahn Kusalo.
In 2008, she took up the formal training at Sati Sārāņīya Hermitage as an anagārikā (postulant) and in 2010 received sāmaņerī (novice) ordination. Both were with Ayyā Medhānandī as her ācarinī (teacher) .
In 2011, she was ordained as a bhikkhunī at Spirit Rock, California with Ayyā Ānandabodhī and Ayyā Santacittā of Aloka Vihāra. The bhikkhunī upasamapda (full ordination) ceremony was performed by a dual Theravāda Sangha of bhikkhus and bhikkhunīs lead by Ayyā Tathālokā Therī, acting as pavattinī (preceptor).
She worked with Ayyā Tathālokā to coedit the 3rd edition of the Pāli-English Bhikkhunī Pātimokkha booklet, printed in 2016 for distribution to the Bhikkhunī Sangha worldwide.