Sword and Shield version of Shiny Chaining involves fighting the same Pokemon repeatedly, to increase the chances of getting a Shiny. There is another way to increase your chances of getting a Shiny; Breeding of eggs with the Masuda method.
How to get Shiny Pokémon using Masuda method egg farming in Sword and Shield
Currently, to get Pokemon Shiny, you can chain yourself by fighting the same type of Pokemon multiple times to increase your chance of getting a Shiny. The Masuda method revolves around breeding two Pokemon of the same species and egg groups, but of different genera and from different regions. Not regions within the game, but regions within the real world. The method will also work with Ditto and Starters.
For example, you can breed an English Pikachu with an opposite-sex Pikachu from Japan, and this will increase the chances that that Pokemon is a Shiny. The Pokemon you are breeding with must have a different "original language", while at least one of them must have the same original language as the region in which you purchased the game. The reason it works is that the game will recognize both Pokemon with different languages and then attempt to find the personality values for the offspring Pokemon which results in a Shiny.
This method will also stack with the shiny charm. The standard chance of getting a Shiny falls between 1 in 2000 or 1 in 4000. By completing your Pokedex and getting a Shiny Spell, the odds can drop between 1 in 600 and 1 in 1000. So, it's still hard to get, but more acceptable than without it. So, if you're serious about getting some Shiny Pokemon, it's time to start doing business with other Trainers around the world.
As soon as the exact odds have been determined, we will update this article.