“Ta-kill-ya” is one of several nicknames for “tequila.” The nickname is said when the tequila is strong.
   
   
Google Books
Mister White Eyes
a novel by Herbert Gold
New York: Arbor House
1984
Pg. 237:
So I practiced drinking that Mexicali Ta Kill Ya and now here I am, smart as any other New Yorker.
   
Google Books
Trukness: Based on the Real Life Adventures and Times of One of the Many Gregory John Nolascos
by Peter J. Crisanto-Croox
Xlibris Corporation
1997
Pg. 17:
3 shots of ta-kill-ya came to pass. 
   
This Dog’ll Really Hunt:
An Entertaining and Informative Texas Dictionary
by Wallace O. Chariton
Plano, TX: Republic of Texas Press
1999:
Pg. 273:
Tequila:
1. Ta-kill-ya
2. Mexican gasoline (or milk)
3. worm medicine  
 
Google Books
The Thinking Person’s Guide to Sobriety
by Bert Plymen
New York: St. Martin’s Press
1999
Pg. 142:
We went to Mexico with several couples, and they all drank tequila (they called it “ta-kill-ya”) with lime salt.