Here is my take -- you could really ask this 3 different ways:
Does LeChatelier's Principle apply in a mash for
1. pressure?
2. temperature?
3. concentration?
For starters, it's really not an equilibrium reaction since a) enzymes are not consumed in a nice stoichiometric way, they are not a reactant or product. It is better to think of them as a catalyst. Amylase enzymes are like the 2 thugs holding a guy by the arms so loan-shark water can punch him in the gut. And b) it does not move both ways. That's the big one if you're specifically talking about LeChatelier equilibrium. That's not to say there aren't ways to get more complete conversion, but if we're being technical and asking about LeChatelier, it's already out the window.
1. Pressure Since these exist as liquid (water) and aqueous (minerals, starches, sugars, enzymes) states, pressure is out.
2. Temperature Let's make an assumption and see what happens.
Heat + long_sugar + water <--amylase--> 2 short_sugar
There are a few problems here. Amylase does not facilitate recombining longer sugars. If you converted the long_sugars 100% and let the mash sit longer, it does not move backward to find an equilibrium of long_sugars. This also implies adding more heat would continue to drive this to the right. Too much heat would denature the amylase so clearly we won't get more short_sugar by adding heat.
It must be more like:
long_sugar + water --amylase(@heat/pH)--> 2 short_sugar
Since it's not specifically endo- or exothermic (to any appreciably significant number as far as I know), we can't write heat as a product or reactant. Therefor changing heat on either side does not draw the process one way or the other. It's just a requisite for the catalyst.
3. Concentration So let's look at just the reaction now.
long_sugar (aq) ---> 2 short_sugar (aq)
You can add more long_sugars to get more short_sugars, sure. But can you dump in table_sugar and have some of it combine to long_sugars? No. It's not LeChatelier.