Bhagavad Gita · Karma Sannyasa YogaChapter 5, Shloka 14 (5.14)

Shankaracharya — the Lord = the self, nature = maya. Na kartṛtvaṃ svataḥ "kuru" iti — the self does not create doership by telling anyone "do it"; nor actions like ratha-ghaṭa-prāsādādīni (a chariot, a pot, a palace); nor the link with their fruit. Then who does? Svabhāvas tu svo bhāvaḥ svabhāvaḥ avidyā-lakṣaṇā prakṛtiḥ māyā pravartate — nature, that is, prakriti in the form of avidya, maya, is what operates — which will later be called daivī hi (7.14). Shankara's conclusion: paramārthatas tu — in ultimate truth the self is a non-doer.

Acharya Ramanuja — nature = beginningless vasana (latent tendency). Ayaṃ prabhuḥ akarma-vaśyaḥ svābhāvika-svarūpeṇa avasthita ātmā — the "Lord" means the self, which is not under the sway of karma and abides in its natural form — it does not create the doership of god, animal, human and so on. Svabhāvaḥ prakṛti-vāsanā — the vasana formed by the association with prakriti, arising from old karma carried on since beginningless time, and by the identification "I am a god / I am a human", drives all this; na svarūpa-prayuktam — not from one's own nature.

The difference: For Shankara, nature = maya (avidya), and non-doership is the ultimate truth; for Ramanuja, nature = karmic vasana, and the self's nature is real, only presently bound to prakriti.