This means that he can pass budgets through the senate with a simple majority, instead of needing 60 votes.
Not exactly... Once per fiscal year (two this calendar year due to delays) the Senate can pass a budget reconciliation bill with a simple majority. This is limited only to budgetary things, so increasing the minimum wage for example wouldn't be allowed. As chairman of the budget committee, Sanders will have a lot of say in constructing any budget reconciliation bills, but he won't completely control the process or anything.
Senate and House chairmen are very influential in directing the flow of legislation, and they can also easily create news by conducting hearings on whatever they want and calling whoever they want as witnesses. I suppose that Sanders will use the position to push for much higher taxes and much higher spending, but the chairmanship is just a particularly good lever: he can't single-handedly
do anything. Keep in mind as well that Democratic leadership wouldn't have made Sanders a chairman if they didn't think that he'd be at least largely controllable by the Democratic party apparatus, so don't expect him to pull any stunts like refusing to cooperate in passing any budgets through his committee if they don't include Medicare for All. Also, AFAIK the Budget Committee is one of the more minor committees; the appropriations committee is more powerful overall in constructing the budget, I think.
Now if the democrats start talking about how the republicans are blocking them on issues like healthcare, stimulus, fighting climate change... They're lying.
True. If all of the Democrats voted as a bloc, then they could get rid of the filibuster and do whatever they want. If anything fails to pass, then it'll ultimately be due to a
bipartisan willingness to let it fail.
Exactly what agreement McConnell and Schumer reach on the Senate rules for the next 2 years will be telling. They haven't reached a deal yet, but it sounds like Democrats are willing to give Republicans a lot of power, and McConnell is even pushing for guaranteeing that the filibuster is preserved.