When the Gita speaks of nature, it usually means prakriti: the whole field of change that includes the elements, the body, the senses and even the mind, along with the three gunas that color them. It is a powerful lens for self-understanding. Much of what we call my mood, my habit or my reaction turns out to be nature at work, which suggests we are more than those things.
Gita 5.14 says actions, doership and results arise from prakriti while the Self remains a detached witness, so recognize the influence of habits and conditioning while cultivating awareness beyond them. Gita 7.4 lists the eight components of nature, including mind, intellect and ego, and Gita 13.20 says nature and the conscious self are both beginningless, with changes and the three qualities arising from nature. Gita 14.5 says goodness, passion and ignorance bind the soul to the body and its experiences.
The Gita also describes how the gunas shape daily life. Gita 14.10 says they are always present together and one prevails at a time, which explains why moods keep shifting, so nurture sattva through healthy habits, good company and reflection. Gita 14.9 says sattva attaches to happiness, rajas to action and tamas to heedlessness, and Gita 14.6 says even goodness binds when we cling to it. Gita 2.45 asks us to rise above the pull of nature's qualities and stay centered.