Veneer chip at back of front tooth. I am extremely hesitant in having the whole veneer replaced. What are my options?

Repairing of veneers is difficult, but if it is in the back, it can probably be given a patched or bonding repair. If the veneer itself; however, has suffered any structural damage, it may need to be replaced. If you feel like your dentist is pushing too hard to replace a veneer that might otherwise be capable of repair with some bonding, I'd seek a second opinion with another dentist. It always pays to see what your options so you can save yourself trouble and money. 

 If the chip is on the inside of the tooth, or lingual as we call it in our
dental world, often times this can roughened up a little bit and then a bonding
resin can be placed to fill in the chip. If the chip is actually a
fracture in the porcelain and your dentist feels that this crack is
compromising the entire veneer or that it might break off completely, they may
want to replace it. My goal is always to try and be as conservative as
possible at first. If the repair fails, the veneer can still be replaced
with no consequences. If the repair is successful, this is a great
service for you.