It's fine to mix in with the protein shake, but I suggest chasing the dose with grapefruit or orange juice. It masks the bad taste pretty well. Just hold some juice in your mouth, squirt in the nolva, swallow, then chase it with more juice.
And the time of day for the dose doesn't matter as long as you're consistent with taking it around every 24 hours. For example, take it every morning with breakfast or every afternoon with your post workout shake. Doesn't matter. Whatever works for you as long as it's around the same time every day.