Old Glory, Star-Spangled Banner, Stars and Stripes
The Australian flag does not have a nickname.
The nickname for the British flag is the Union Jack. Although it is only correctly known as this when flown on a ship.
Wyoming's flag has an American Bison in the center (as the state's nickname is the "Buffalo State"). The white bison is charged in a field of blue; the boarder of the flag is white and red.
The compound noun Old Glory is a proper noun, a nickname for the American flag. A nickname is a name for a specific person or thing. A proper noun is always capitalized.
The third flag of the Confederacy was called the Stainless Banner
because it did
The American Flags nickname is Old Glory.
The American flag is called the Grand OldFlag.
The Australian flag does not have a nickname.
Wyoming's state flag does not have a nickname. However, the state of Wyoming's official nickname is "The Equality State" which appears on Wyoming's state flag.
Mexican Flag
It doesn't have any nickname.
The nickname for the British flag is the Union Jack. Although it is only correctly known as this when flown on a ship.
Wyoming's flag has an American Bison in the center (as the state's nickname is the "Buffalo State"). The white bison is charged in a field of blue; the boarder of the flag is white and red.
"Stars and stripes", "The Red, White, and Blue".
The American Flags nickname is neither. Its Old Glory.
The Tricolor