- Link: samuelgr/Xidi: DirectInput interface for XInput controllers [github.com]
Click on the latest release and download Xidi.zip.

- Copy "Win32/dinput8.dll" to "Splinter Cell Chaos Theory\System\".

- Create "System\xidi.ini" and add these lines:

[Mapper]
Type = Custom

[CustomMapper]
StickLeftX = Axis(X)
StickLeftY = Axis(Y)
StickRightX = Axis(Z)
StickRightY = Axis(RotZ)
DpadUp = Pov(Up)
DpadDown = Pov(Down)
DpadLeft = Pov(Left)
DpadRight = Pov(Right)
ButtonA = Keyboard(Enter)
ButtonB = Button(2)
ButtonX = Button(3)
ButtonY = Button(4)
ButtonLB = Button(5)
ButtonRB = Button(6)
TriggerLT = Button(7)
TriggerRT = Button(8)
ButtonBack = Button(9)
ButtonStart = Button(10)
ButtonLS = Button(11)
ButtonRS = Button(12)

- Edit "%PROGRAMDATA%\Ubisoft\Tom Clancy's Splinter Cell Chaos Theory\Joysticks.ini" and change these lines:

[Joystick0]
ProductName=Xidi Virtual Controller 1
VendorID=65535
ProductID=1
AxisStrafe=Axis_X
AxisForwardBackward=Axis_Y
AxisTurnHead=Axis_Z
AxisLookUpDown=Axis_Rotation_Z
Joy1=Interaction
Joy2=Duck
Joy3=QuickInventory
Joy4=Jump
Joy5=ZoomToggle
Joy6=AltFire
Joy7=Scope
Joy8=Fire
Joy9=OpsatMenu
Joy10=PauseMenu
Joy11=SwitchHandZoom
Joy12=CoopActionWhistle
Joy13=DpadUp
Joy14=DPadDown
Joy15=DPadLeft
Joy16=DPadRight
DPadUp=EEVMode
DPadDown=StickyCamMode
DPadLeft=NightVision
DPadRight=ThermalVision

- Edit "%PROGRAMDATA%\Ubisoft\Tom Clancy's Splinter Cell Chaos Theory\SplinterCell3User.ini" and change these lines:

Joy1=Interaction
Joy2=Duck
Joy3=QuickInventory
Joy4=Jump
Joy5=ZoomToggle
Joy6=AltFire
Joy7=Scope
Joy8=Fire
Joy9=PauseMenu
Joy10=OpsatMenu
Joy11=SwitchHandZoom
Joy12=CoopActionWhistle
Joy13=DpadUp
Joy14=DPadDown
Joy15=DPadLeft
Joy16=DPadRight
JoyX=Axis aStrafe DeadZone=0.2
JoyY=Axis aForward DeadZone=0.2
JoyZ=Axis aTurn DeadZone=0.2
JoyV=Axis aLookUp DeadZone=0.2
JoyR=
JoyU=
XBoxControllerAxis=true
AnalogUp=AnalogUp
AnalogDown=AnalogDown
AnalogLeft=AnalogLeft
AnalogRight=AnalogRight
FirstRepeatDelay=0.5
RepeatDelay=0.1
AnalogThreshold=0.8
UseAnalogAsPad=true

- Disable Steam Input:
Navigate to "Tom Clancy's Splinter Cell: Chaos Theory> Properties> Controller> Disable Steam Input".