I was trying to get my friend to watch me on Minecraft, (I launched it through Steam), and it said that it was waiting for my broadcast to start. (No overlay)
How do I add the Steam overlay on my Minecraft?
You would have to add Minecraft as a non-steam game.
Go to Steam and click "Add Non-Steam Game to My Library", then select Minecraft or find Minecraft.exe.
C:\Program Files (x86)\Minecraft\MinecraftLauncher.exe
for the "target area" and C:\Program Files (x86)\Minecraft
for the "Start In" area.