Attenborough, whose career spans more than 50 years, appeared with the World Health Organisation and Belarusian dissident Sviatlana Tsikhanouskaya on the shortlist.
Swedish climate activist Greta Thunberg, the Myanmar National Unity Government formed by opponents of last year's coup, and Tuvalu's Foreign Minister Simon Kofe are also in the running, last-minute announcements showed.
Kremlin critic Mr Navalny is imprisoned in Russia and his political and activist networks have been outlawed.
Thousands of people, from members of parliaments to former winners, are eligible to propose candidates.
The Norwegian Nobel Committee, which decides who wins the award, does not comment on nominations, keeping secret for 50 years the names of nominators and unsuccessful nominees.
However, some nominators decided to reveal their candidates.
Attenborough, 95, is best known for presenting television series illustrating the natural world, such as Life on Earth and The Blue Planet.
He was nominated jointly with the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, which assesses the state of biodiversity.
They were put forward for "their efforts to inform about, and protect, Earth's natural diversity, a prerequisite for sustainable and peaceful societies", said nominator Une Bastholm, the leader of the Norwegian Green Party.
Another Green Party representative nominated Ms Thunberg, who has inspired young people to resist climate change.
Pope Francis was nominated for his efforts to help solve the climate crisis, as well as his work towards peace and reconciliation, by Dag Inge Ulstein, a former minister of international development in Norway.
Mr Kofe was nominated by the leader of Norway's Liberal Party, Guri Melby, for his work in highlighting the effects of global warming. He filmed a speech to last year's Cop26 climate conference standing knee-deep in seawater.
Nominations, which closed on Monday, do not imply an endorsement from the Nobel committee.
The 2022 laureate will be announced in October.