Firstly, go to the game properties and switch the "Steam Input Per-Game Setting" tab to "Forced Off". This might not be a requirement but it is recommended.

Next simply boot the game with your controller connected and then exit out.

Navigate to "C:\ProgramData\Ubisoft\Tom Clancy's Splinter Cell Chaos Theory". Note you will need to enable "Hidden Items" in the View tab of Windows Explorer in order to find the "ProgramData" folder.

Open the file "Joysticks.ini". This is a list of all your previous controller configurations. The entry you are looking for begins with:

ProductName=Wireless Controller
VendorID=1356

Select all the text from "AxisStrafe=Axis_X" down to "DPadRight=ThermalVision" and replace it with:

AxisStrafe=Axis_X
AxisForwardBackward=Axis_Y
AxisTurnHead=Axis_Z
AxisLookUpDown=Axis_Rotation_Z
Joy1=Scope
Joy2=Interaction
Joy3=Duck
Joy4=Jump
Joy5=QuickInventory
Joy6=CoopActionWhistle
Joy7=AltFire
Joy8=Fire
Joy9=OpsatMenu
Joy10=PauseMenu
Joy11=SwitchHandZoom
Joy12=ZoomToggle
Joy13=
Joy14=QuickSave
Joy15=
Joy16=
DPadUp=EEVMode
DPadDown=StickyCamMode
DPadLeft=NightVision
DPadRight=ThermalVision

Save the file and you are done. You can now play Splinter Cell Chaos Theory with a wired DualShock 4.

The setup for a wireless connection is similar to wired but has quite an annoying restriction. You MUST go to Steam's Controller Settings and un-check the option "PS4 Configuration Support". Windows cannot detect dinput from a wireless DualShock 4 whilst Steam is interfering.

Now go to Windows Bluetooth settings and pair your controller. To put the DualShock 4 into pairing mode, hold the "Share" and "PS" buttons simultaneously until the light bar starts flashing.

If you have already setup a wired connection you will now be good to go. If not then continue reading.

Go to the game properties and switch the "Steam Input Per-Game Setting" tab to "Forced Off".

Boot the game with your controller connected and then exit out.

Navigate to "C:\ProgramData\Ubisoft\Tom Clancy's Splinter Cell Chaos Theory". Note you will need to enable "Hidden Items" in the View tab of Windows Explorer.

Open the file "Joysticks.ini". This is a list of all your previous controller configurations. The entry you are looking for begins with:

ProductName=Wireless Controller
VendorID=1356

Select all the text from "AxisStrafe=Axis_X" down to "DPadRight=ThermalVision" and replace it with:

AxisStrafe=Axis_X
AxisForwardBackward=Axis_Y
AxisTurnHead=Axis_Z
AxisLookUpDown=Axis_Rotation_Z
Joy1=Scope
Joy2=Interaction
Joy3=Duck
Joy4=Jump
Joy5=QuickInventory
Joy6=CoopActionWhistle
Joy7=AltFire
Joy8=Fire
Joy9=OpsatMenu
Joy10=PauseMenu
Joy11=SwitchHandZoom
Joy12=ZoomToggle
Joy13=
Joy14=QuickSave
Joy15=
Joy16=
DPadUp=EEVMode
DPadDown=StickyCamMode
DPadLeft=NightVision
DPadRight=ThermalVision

Save the file and you are done. You can now play Splinter Cell Chaos Theory with a wireless DualShock 4.

If you're using a Wireless connection and have disabled "PS4 Configuration Support" you will now want to change the properties of your games that use custom configurations. Go to each game's properties and select "Forced On" under "Steam Input Per-Game Setting".