Nixon was more liberal than today's democrats. Apart from the whole Vietnam thing.
And the Cambodia thing...
Or sabotaging the 1968 peace talks because war was good politics...
Or that whole coup in Chile that we were just arguing about...
But I'm guessing you mean his domestic policies where he supported a health insurance reform and signed the EPA into existence.
So, the EPA. Nixon signed it but the EPA was also a product of the time, a democratic congress wanted more conservation efforts and Nixon went along with it. Compare that to "today's democrats" who want to broadened power for the EPA (carbon regulation) and just won a very long and contentious political battle over the scope of the EPA. And the EPA in Nixons time wasn't regulating carbon. So democrats are not only supporting a policy more far reaching then what Nixon supported but they were supporting it when it was politically difficult, unlike Nixon.
And then we have Nixon's healthcare policies. He didn't have an individual mandate, instead he had an employer mandate. And he wanted to replace medicaid with block grants to states so that the south could start taking healthcare away from black people. There would be cost-sharing, but in those state run block grant programs. There was nothing the equivalent of the exchanges with the income based subsidies. Compare that to what the left wing of the democrats got the right wing of the democrats to agree to: subsidies to the poor, expansion of medicaid, cost sharing through the insurance pools.
And of course the whole war on drugs and tax cuts for the rich.
Nixon wasn't a reliable conservative in a way that kinda reminds me of Trump, TBH. He was very politically expedient, eager to play "the great game" even though it was an anachronism.