I'm not a lefty but I've always liked using the numpad instead of WSAD. Since Chex Quest HD doesn't support rebinding controls I have created a simple AHK script which gives me the controls I use in every other FPS.

Chex Quest HD' default controls are:

W = Move Forward
S = Move Backward
A = Move Left
D = Move Right
Spacebar = Jump

E = Interact / Use
Y = Speak
Mousewheel = Change Weapons
Mouse Button 1 = Fire Weapon

1. Download and Install Autohotkey https://www.autohotkey.com/
2. Create a text file with the following contents:

NumpadEnter::Space
Numpad8::w
Numpad2::s
Numpad4::a
Numpad6::d
Numpad5::e
Numpadadd::y

3. Save the file (mine is called Chex_Quest_HD_Rebinds) in any folder you like or even on the desktop.
4. Manually change the file extension to .ahk in Windows Explorer.
5. Run the file Chex_Quest_HD_Rebinds.ahk before starting the game

This effectively makes the computer think that I'm pressing Spacebar when I'm actually pressing Pad Enter (for example).

6. To restore the keyboard to normal when you're done playing simply right-click the script in your system tray and hit [Exit]. The system tray icon is

Of course you can alter the contents of the .ahk file according to your desired bindings. You put the name of the key you want on the left side of the :: and the key it is mimicking on the right side.

For example, say you want to to use IKJL to move forward, back, left, and right. The text of your script should be as follows:

i::w
k::s
j::a
l::d

Autohotkey requires specific names for keys in order to work. the list of exact names is here:
https://www.autohotkey.com/docs/KeyList.htm

Happy Zorching!