Very easy to detect by a regex since it’s always 0x and then 40 characters a-f and numbers.
/^0x[a-fA-F0-9]{40}$/g
BTC addresses would be ^[13][a-km-zA-HJ-NP-Z1-9]{25,34}$ (13 followed by 25 to 34 characters, excluding l, I, O and 0)
Add this to watched words and don’t forget to enable settings - posting - “watched words regular expressions”.