Tennessee's "Stand your ground" laws haven't changed in several years. You have the right to self-defense not only in your home, but pretty much anywhere you are lawfully entitled to be, such as in your car, walking down the sidewalk, etc. This includes your place of business. Also, there is no duty to retreat.
Basically it hinges on whether that standard-issue "reasonable person" would agree that you acted in self-defense because you were (again, reasonably) in fear of the other person and that you felt at the time that you could suffer a serious injury or the person might kill you.
It is worth pointing out that none of the above justifies use of deadly force in defense of, or protection of, property per se.
If you confront someone intent on destroying your property and they transfer their destructive intent to you, then you're back to the preceding paragraph.
Statute(s)
Tennessee Code, Title 39, Chapter 11, Section 39-11-611 (Self-Defense)
When the Use of Deadly Force Is Justified
A person who's in a place lawfully and who isn't engaged in an illegal activity has no duty to retreat before using or threatening to use force that's likely to cause serious bodily injury or death if:
The person reasonably believes there's an imminent danger of serious bodily injury or death;
The danger is real or honestly believed to be real at the time; and
The belief of danger is founded upon reasonable grounds.
A person who uses deadly force within a residence, business, dwelling, or vehicle is presumed to have held a reasonable belief of imminent death or serious bodily injury to self, family, a member of the household or a person visiting as an invited guest when the force is used against someone who unlawfully and forcibly entered the place.
When the Use of Force Is Not Justified
The use or threat of force isn't justified in the following situations:
If you consented to the exact force used by the other person.
If you provoked the other person's use of unlawful force, unless: (1) you abandoned the encounter (physically or via clear communication); and (2) the other person continues to use unlawful force.
If you resist a halt at a search, arrest, roadblock, or stop and frisk that you know is being conducted by a police officer, unless: (1) the officer uses greater force than necessary; and (2) the person using force reasonably believes that the force is immediately necessary to protect against the officer's unnecessary use of force.
Related Statute(s)
Tennessee Code, Title 39, Chapter 11:
Section 39-11-612 (Defense of Third Person)
Section 39-11-613 (Protection of Life or Health)
Section 39-11-614 (Protection of Property)
Section 39-11-615 (Protection of Third Person's Property)