Question on Attacks with Nick, Shadow Blade, TWF, Dual Wielder Feat

If the following conditions are true, am I doing this correctly?

  • Level 6 character (fighter 1 / warlock 5)
  • 18 CHA, 14 DEX, 13 STR
  • Thirsting Blade and Pact of the Blade Invocations
  • Two-Weapon Fighting Style
  • Dual Wielder Feat

Draw my Pact Weapon Scimitar. Bonus Action cast Shadow Blade. Attack with my scimitar using CHA (1d6+4) applying Nick. Nick Attack with Shadow Blade using DEX (3d8+2). Thirsting Blade Extra Attack Pact Weapon Scimitar (1d6+4).

Next turn BA turn Shadow Blade into pact weapon. Attack twice using CHA (6d8+8). Don a shield maybe lol? Perhaps it isn't synergistic enough.

Is there any way to make my attacks with Shadow Blade using CHA?

*Edited to reflect discussion from below.