Is this sentence grammatically wrong?

Question

Had Nick been here on time, we would not have missed the train. [Introduction]
Had Nick been here on time, we would not miss the train.

Is the second sentence grammatically wrong, or are the two sentences different just in their nuance?

Answer 1

Standing on the train platform today, waiting for Nick, you might say, anxiously:

“If Nick is here we will not miss the train.”

If you narrate this tomorrow, you will backshift the tenses:

“Yesterday I said that if Nick was here we would not miss the train.”

Now suppose that in fact Nick is not on time. Now your condition, your IF clause, is an irrealis or counterfactual. Just before the train leaves you might say, despairingly:

“If Nick were here we would not miss the train.”

And afterwards, as the train pulls out of the station, leaving you on the platform, you might say bitterly:

“If Nick had been here we would not have missed the train.”

What is confusing here is that would does double duty: it may act as either the past indicative form or the present conditional form of will. You have to figure out which is in play from the context.

Answer 2

The second is an ungrammatical way of expressing the first. The first part of the sentence imagines something that didn't happen in the past, whereas we would not miss the train envisages some present or future event. An example of its use might be If you weren't so late getting to the station every day, we wouldn't miss the train so often.

Answer 3

{Had it been} {that would have} - is the rule.

Hence the first sentence is correct and the second one is not.