Short answer. Yes. This is called a simple substitution. You may designate one or more persons to take the place of an instituted heir who dies before you, does not wish to accept, or is incapacitated to inherit. The substitute steps in only if the first choice falls out for one of those reasons.
What the law says
The testator may designate one or more persons to substitute the heir or heirs instituted in case such heir or heirs should die before him, or should not wish, or should be incapacitated to accept the inheritance.
Civil Code, Article 859 — Simple Substitution. Read the full provision →
A substitute is expressly allowed
Article 859 lets you build a fallback into the will: the testator may designate one or more persons to substitute the heir or heirs instituted in case such heir or heirs should die before him, or should not wish, or should be incapacitated to accept the inheritance. So you are not confined to naming a single line of heirs and hoping each is willing and able. You may appoint a second choice, or several, to catch the share if your first choice cannot or will not take it. The substitute inherits in the first heir's stead, receiving what that heir would have received.
The three situations it answers
The article names three distinct events that can open the way for a substitute: the instituted heir dies before you, so the gift never vests in him; he is alive but does not wish to accept and renounces; or he is incapacitated to inherit, disqualified by law from taking. Each is a way the primary institution can fail, and a substitution is the mechanism that keeps the property within your chosen plan rather than letting it fall to intestacy. You are free to provide for one, some, or all of these contingencies.
Say nothing, and it covers all three
If you simply name a substitute without spelling out when he takes, the law reads it broadly. A simple substitution stated without specifying the cases comprises all three, predecease, refusal and incapacity, unless you have provided otherwise. That default usually matches what testators want: a genuine backup for whatever reason the first choice drops out. If instead you mean the substitute to inherit only in one of those events, say so expressly, because silence is read as covering the full set, not the narrow one.
Draft it clearly, and mind the legitime
Name both the primary heir and the substitute plainly, and if you want to limit the triggering events, state the limitation. Bear in mind that substitution operates within what you are free to dispose of; it cannot be used to divert or encumber the legitime that the law reserves for your compulsory heirs. So a substitution is a powerful tool over your disposable portion and over gifts to voluntary heirs, but the reserved shares of your compulsory heirs follow their own rules. A lawyer can frame the clause so it does the work you intend without overreaching.