What does the cryptic crossword clue "Unstable reign in landlocked African country (5)" mean?

The definition is "African country". The wordplay uses an anagram. anagram of REIGN = NIGER; definition: "African country" The answer is NIGER.

Unstable reign in landlocked African country (5)

Daily Mail Cryptic #17143 | 14 Down | 2023-07-18 flower