It's fairly easy to make too. All you need is, tobacco, NaCl, CaCO3 and an oven that can keep the temperature at 95C. If you want you can go fancy with additives and flavouring.
Here's my recipe
500g of finely ground tobacco (I think Kentucky is the usual strain).
60g NaCl
500g water
Mix ingredients and shove it in the oven for 24 hours.
Remove the container, go outside and add 50-60g of CaCo3 (this decides the strength both feel and actual nicotine).
Put it back in the oven for 12 more hours and add water to taste (1-2.5dl).
If possible, add 5ml of liquid smoke in the first step.
If you want to go fancy add, gum arabic (20-30g), maltodextrin (20g), glycerol (20-30g) and propylene glycol (20-30g) as a last step.