After attempting to activate the Main Control Unit in Nabooris, Thunderblight Ganon attacks.
This can be a difficult battle. Equip a non-metallic shield if you have one. Also, if you have the upgraded Rubber Armor set, equip it for some protection from the electric attacks you will face. However, you will still be damaged by electricity. The rubber armor will just prevent you from dropping your weapon and shield if shocked.
You might want to practice Perfect Guards and Perfect Dodges before this battle. They are very useful skills here. Perfect Guards are performed by raising your shield with ZL, then pressing A before an attack hits. Time will slow down and you will knock back projectiles and attacks, and you can do a Flurry Rush by tapping Y afterward. Perfect Dodges are performed by side hopping or backflipping just before an attack hits you. As with Perfect Guards, time will slow and you can tap Y to do a Flurry Rush afterward.
Equip a one-handed weapon and a shield (preferably a non-metallic shield if you have one). You can avoid the green lightning balls fairly easily, but they can bounce off of walls, so keep an eye on them. Keep your shield raised when Thunderblight Ganon moves quickly toward you. With your shield raised, you will automatically block its attack. When you have learned the timing of this attack, do a backflip just before the attack to do a Perfect Dodge, or press A to parry with your shield to do a Perfect Guard, allowing you to do a Flurry Rush afterward.
The second phase starts when you reduce Thunderblight Ganon's health to 50%. Run away from the metal pillars that Thunderblight Ganon creates near you, and walk onto a raised walkway. When the pillars stop falling, use Magnesis to grab one and move it close to Thunderblight Ganon. When the lightning strikes, you can run over to Thunderblight Ganon and attack.
Thunderblight Ganon will go back to his earlier attack pattern, but this time his weapon will sometimes be electrified. If you don't have a non-metallic shield, you will have to just wait until the weapon's electricity goes away. He will also sometimes do a series of slashes with his weapon instead of just one like in the previous phase.
Thunderblight Ganon might also aim a red laser at you and then attack with a laser blast. If you are confident in your ability to do Perfect Guards, you can knock the energy back at Ganon (raise your shield, then press A just before the laser hits). Otherwise, hide behind something or run sideways to avoid the laser.
You can also try to destroy Ganon's shield. You will need a weapon with high durability, but breaking through his shield will allow you to attack immediately at close range. Just be aware that he will regenerate his shield quickly if he is aiming a red laser at you, so you should just run away or prepare to do a Perfect Guard before the laser blast hits.
Get the Heart Container. If you are done exploring Nabooris, you can activate the Main Control Unit. After that, you won't be able to re-enter Nabooris, so you might want to use your Sheikah Sensor to search for treasure chests that you might have missed.
After activating the Main Control Unit, you get Urbosa's Fury. Hold Y to make lightning strike near you. You can disable Urbosa's Fury in your Inventory in the Key Items section.
You will be outside Gerudo Town. Equip your Gerudo vai clothing and go to the throne room to talk to Riju. This completes the Divine Beast Vah Nabooris quest. Open the chests behind Riju's throne to get a sword and shield that belonged to Urbosa.