The speaker of "Ode to a Nightingale" loves nature, but he can't get on board with the whole natural-things-have-to-die-sometime thing. He even fancies that the nightingale is some immortal, godlike creature. However, nature is his best hope for escape from the world of work, stress, responsibility, and complicated human relationships. Although he begins the poem sitting just outside of a wooded area, he will not be satisfied until he can experience the forest from the perspective of one of its creatures: from the inside. He imagines becoming intoxicated from the smells of all the forest plants and flowers.
The speaker admires the nightingale because it transcends the natural cycle of life and death through its immortal song.
The poem's central conflict is driven by the speaker's desire to transform and reinvent nature to fit his own desires.