I think you're going to have to be a little more specific - a 99 Vitara wouldn't have a "drive chain" as such, unless you're referring to the chain in the transfer case (assuming it's a 4WD).
The transfer case chains generally don't give trouble, and if it were to fail, I don't think you would diagnose that using codes. Cost of repair would depend on what exactly failed, but I suspect you could get a used transfer case at a reasonable price, I certainly can.
The other chain on the vehicle is the timing chain, which it may or may not have, depending on the engine - again the diagnosis for a failed chain wouldn't normally be made via codes - that would make for a significantly more expensive repair as it usually involves a rebuilding the cylinder head(s) and replacing bent valves, again repair costs will vary depending on the extent of the damage.
You're saying around 2K to fix/replace the motor, so that sounds like timing chains - you don't have to be car smart to make a decision on this - the decision can be made purely as a financial consideration - what will it cost you to replace the Vitara with something comparable?
If it's more than 2K, that would be one reason to fix it. What condition is the rest of the car in? What will you replace it with? A 1999 Vitara is a twenty four year old vehicle, if yours has been well maintained it might be worth keeping, mine is a 98 and I would quite willingly spend 2K (assuming USD$) to keep it on the road. Part of my willingness is that the Vitara is a fairly unique vehicle, no one other than Suzuki makes small 4WDs with two speed transfer cases, maybe that "uniqueness" isn't important to you, and if that's the case it opens up the available replacement pool considerably.
If all you're looking for is basic transportation you might be able to find a smaller, newer vehicle for not much more than 2K that might be a suitable replacement, that is not the case for me, so my choice would be to spend the 2K. If funds are tight it can be a tough decision, it's an old car, would if I spend say 2.5K to get it rolling and next week something else breaks, what if you spend 3K on a newer vehicle and next week something breaks? You can't predict the future and neither can we.
This a decision that only you can make, we don't know your situation, your finances, your vehicle needs, etc.
One last thing - if you're not car smart, parting it out is not an option for you, selling it as is might be - parting it out involves removing the parts and selling them, it's going to require the ability to remove the parts, pack them & ship them, it's going to require space to store the vehicle and work on it and at some point you're going to be left with a pile of junk that's missing wheels, axles and Lord knows what else that will have to be hauled away.
