https://issuesinsights.com/2020/11/14/could-illegal-voters-hand-the-election-to-joe-biden/
Based on current population data from the Census Bureau and voting data from previous elections, Just Facts has conducted a study to estimate the number of votes illegally cast by non-citizens in the battleground states of the 2020 election. The results—documented in this spreadsheet—show that such fraudulent activities have netted Joe Biden the following extra votes in these tightly contested states:
Arizona: 51,081 ± 17,689
Georgia: 54,950 ± 19,025
Michigan: 22,585 ± 7,842
Nevada: 22,021 ± 7,717
North Carolina: 46,218 ± 16,001
Pennsylvania: 32,706 ± 11,332
Wisconsin: 5,010 ± 1,774
If the lower end of these illegal vote estimates were removed from the vote tallies as of November 8, 2020, 2:00 AM EST, Donald Trump would be leading in states that have a total of 259 electoral votes, or 11 shy of the 270 needed to win the presidency. If the upper end of the illegal vote estimates were removed, Trump would be leading in states that have 285 electoral votes, or 15 more than needed to win the presidency.
These estimates account for just one type of election fraud, and they tend to understate it because they depend on Census surveys, which are known to undercount non-citizens.